Saturday through Tuesday December 20-23, 2014

Saturday through Tuesday December 20-23, 2014               Updated 8AM Dec 20

SATURDAY          SUNDAY           OUTLOOK FOR MONDAY & TUESDAY

                        

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable.  Since the last large storm Tuesday, Dec 16th, Thompson Pass has seen strong wind winds from varying directions. These winds moved a lot of snow and created slabs throughout our exposed terrain, especially near the Thompson Pass Gap where they were strongest (see activity below). After Saturday, the strong outflow northerly winds are forecast to decrease.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are likely on multiple aspects after onshore winds accompanying Tuesday Dec 16th’s storm, came from the SE, then switched to strong outflow winds dominated from the NE. This has led to many reported natural and skier triggered activity in our forecast area.

List of Avalanche Problems <here>

TRAVEL ADVISORY:  Continually evaluate your terrain choices and the consequences of a slab avalanche, especially in steep terrain features. Look for trends in slab formation and be on the look out for recent avalanche activity, cracking, and whumphing.

AVALANCHE ACTIVITY: 

-Dec 19 (seen Fri, but likely occurred during or just after the last storm: slightly blown in)

  • Lower Python Face 3000-2000′: Large north-facing D2.5 natural slab avalanche: Crown 400-500 wide x 2 ft tall at steep convexity just above alder-line and ran 1000 ft to the flats below. Rocks and trees exposed in the crown face and bed surface.
  • Cracked Ice-Python Drainage 3000-4000′: Two D1 and one D2 natural slab slides into the drainage. NE facing 1-2 ft crowns at steep convexity just below ridge line, wind loaded from the South.

-Dec 18

  • Catchers Mitt 4000′: A couple large, natural, slab avalanches were faintly seen through the clouds down the NE ridge toward Worthington.
  • Moonlight Basin 3200′: Small skier released winds slab pockets on rollovers; localized shooting cracks; few settlements lower down
  • MP 54 – Continental: Numerous large whumphing (snow settlement) below treeline.

-Dec 16

  • Gap at Thompson Pass: one size 2 slab release
  • Wilbur’s at Milepost 40: one size 2.5-3 reached the valley floor
  • Rice Mountain, MP 54: Size 2.5 avalanches with 3 ft crown (ran from ridge to brushline)
  • Numerous point release storm snow avalanches to size 2 released off steep features

Avalanche sizing using the destructive scale <here>

Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Strong winds from the SE, then reversing to the NE, have extensively moved around the 2 feet of new snow that has fallen in the last week. Many people have seen the resulting slab activity this has produced in our area. Luckily, time allows these new slabs to stick and bond to the surrounding snow. As these new upper layers strengthen, still keep an eye out for unsupported slabs in steep terrain features.

Deeper in the snowpack is a more interesting variety of weaknesses.  Two melt freeze crusts seem the be the biggest problems with facets above and below. For the most part, these layers seem less sensitive than previously; requiring more force than before to initiate failure.  Something observed Friday was that there is a slight difference in results depending on where one is in the region. Closer to Thompson Pass which sees warmer temperatures, the facets (sugar snow) above the crusts tend to be the weak points (ECTP 21, 22 RP), with strong pencil hard facets near the ground.  On the other hand, when further inland, where it’s colder, the upper facets are not as sensitive and failure is directed down below the crusts to fist hard facets near the ground (ECTP 24 BRK).

WEATHER:  Strong northerly winds Saturday with increasing cloud cover. Sunday looks like scattered snow (slight chance of rain in town if temps edge above freezing) that will increase in the afternoon and into Monday, before dying out early Tuesday morning. A total of 6 inches of new snow could accumulate by Tuesday.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/20 AM  12/18 AM
Current Snow Depth 5.0″
36″
24 Hour Snow / Water Equiv. 0″ / 0″ 0″ / 0″
December Snow / Water Equiv. 22″ / 1.9″ 52″ / 5.1″
Total Winter Snowfall / Water Equiv.
27″ / 1.00″ 121″ / 13.1″
Snowload in Valdez 7.7 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

NEWS:

Learn about recognizing avalanche terrain and decision making in the Avalanche class Level 1 January 9-11, 2015.

Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Friday through Monday December 19-22, 2014

Friday through Monday December 19-22, 2014               Updated 8AM Dec 19

FRIDAY                SATURDAY           OUTLOOK FOR SUNDAY & MONDAY

               

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable.  On Tuesday, Dec 16th, Thompson Pass received a large storm event with strong wind. The days following the storm, north wind moved the new storm snow. This has created dangerous wind slab instability in wind exposed terrain (see below). As winds let down and the snow settles into its new home, the danger will decrease.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are expected on multiple aspects after onshore winds accompanying Tuesday Dec 16th’s storm, came from the SE, then switched to strong outflow winds dominated from the NE. This has led to many reported natural and skier triggered activity in our forecast area.

List of Avalanche Problems <here>

TRAVEL ADVISORY:  Continually evaluate your terrain choices and the consequences of a slab avalanche. Consider where the recent strong winds have created touchy slabs – they exist on multiple aspects. Look for trends and be on the look out for recent avalanche activity, cracking, and whumphing.

AVALANCHE ACTIVITY: 

-Dec 18

  • Catchers Mitt 4000′: A couple large, natural, slab avalanches were faintly seen through the clouds down the NE ridge toward Worthington.
  • Moonlight Basin 3200′: Small skier released winds slab pockets on rollovers; localized shooting cracks; few settlements lower down
  • MP 54 – Continental: Numerous large whumphing (snow settlement) below treeline.

-Dec 16

  • Gap at Thompson Pass: one size 2 slab release
  • Wilbur’s at Milepost 40: one size 2.5-3 reached the valley floor
  • Rice Mountain, MP 54: Size 2.5 avalanches with 3 ft crown (ran from ridge to brushline)
  • Numerous point release storm snow avalanches to size 2 released off steep features

-Dec 10-15

  • A few human-triggered windslab avalanches on steeper convexities
  • Snow roller balls, indicators of new snow instabilities, were observed with the warm temperatures

Avalanche sizing using the destructive scale <here>

Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   With 2 feet of fresh snow in the last week and strong winds to push it around, various new wind slabs have formed that will need time to settle and bond with the old surfaces. Testing Thursday Dec 18th showed these interfaces still need a chance to strengthen.

Below this new snow is a variety of weaknesses deeper in the snowpack.  The upper two melt freeze crusts seem the be the biggest problems with facets above and below. These layers seem less sensitive than previously; requiring more force than before to initiate failure (ECTP 21, 22).  Meanwhile, the facets (sugar snow) in between the lower crusts and down near the ground continue to gain strength.

WEATHER:  Light snow returns Friday for a bit, then will let up until another light episode starts Sunday night. Moderate to strong winds will linger into Friday and then back down until Monday. Great news…..NO RAIN!

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/19 AM  12/18 AM
Current Snow Depth 5.0″
36″
24 Hour Snow / Water Equiv. 0″ / 0″ 0″ / 0″
December Snow / Water Equiv. 22″ / 1.9″ 52″ / 5.1″
Total Winter Snowfall / Water Equiv.
27″ / 1.00″ 121″ / 13.1″
Snowload in Valdez <5.2 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

NEWS:

Learn about recognizing avalanche terrain and decision making in the Avalanche class Level 1 January 9-11, 2015.

Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Wednesday through Saturday, December 17-20, 2014

Wednesday through Saturday December 17-20, 2014               Updated 8AM Dec 18

WEDNESDAY         THURSDAY          OUTLOOK FOR FRIDAY & SATURDAY

         

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable.  Although the danger of storm snow avalanches decreases as the significant new snow settles, the danger of windslab avalanches increases with Thursday’s forecast strong winds.

AVALANCHE PROBLEM:

Storm-Snow

 

Storm Snow Avalanches - releasing with the heavy snow accumulations above 2000 feet elevation.

 

Wind-Slab iconWind Slab Avalanches –  are expected on slopes loaded with the new snow by Tuesday December 16ths accompanying onshore southerly winds. Both natural and human triggered avalanches will be expected when the winds change direction and slopes become loaded with strong outflow northerly winds.

List of Avalanche Problems <here>

TRAVEL ADVISORY:  Tread lightly in avalanche terrain. There’s a lot of new snow and it isn’t entirely glued to the mountains. Expect to easily trigger slab avalanche on test slopes.

AVALANCHE ACTIVITY:   One size 2.5-3 off Wilbur’s at Milepost 40 reached the valley floor as well as numerous point release storm snow avalanches to size 2 observed to have released off steep features Tuesday December 16. Also, one size 2 slab release at the Gap at Thompson Pass. Snow roller balls, indicators of new snow instabilities, were observed with the warm temperatures December 15. A few human-triggered windslab avalanches on steeper convexities December 10-15.

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Although ten inches of new snow accumulated at Thompson Pass Tuesday, the convective nature of the storm and the periods of heavy rainfall in the valley suggest there could easily be areas with significantly greater amounts of new snow. One and a half inches of water were recorded at the Milepost 12, which could easily translate into 18 inches of snow above the freezing line. However, only half of that was recorded six miles north at Milepost 18. There are two feet of soft snow at Thompson Pass available for wind transport.

The new snow sits over a mixed bag of weaknesses deeper in the snowpack, which is expected during the early part of winter, and one reason Europeans traditionally didn’t start winter activities in avalanche terrain until after the New Year.

WEATHER:  Sunny breaks and screaming northerlies Thursday and Saturday. Another snowflake or two is possible heading into and out of the weekend.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/18 PM  12/18 AM
Current Snow Depth 5.0″
36″
24 Hour Snow / Water Equiv. 0″ / 0″ 0″ / 0″
December Snow / Water Equiv. 22″ / 1.9″ 52″ / 5.1″
Total Winter Snowfall / Water Equiv.
27″ / 1.00″ 121″ / 13.1″
Snowload in Valdez <5.2 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

NEWS:

Learn about recognizing avalanche terrain and decision making in the Avalanche class Level 1 January 9-11, 2015.

Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Tuesday through Friday December 16-19, 2014

Tuesday through Friday December 16-19, 2014               Updated 8AM Dec 16

TUESDAY         WEDNESDAY          OUTLOOK FOR THURSDAY & FRIDAY

         

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable and will remain steady as sensitive snow features exist and more significant precipitation should arrive Tuesday afternoon on Thompson Pass.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are likely and have occurred recently (see below) on slopes loaded from previous outflow northeasterly winds and more recent onshore southeast winds with this new storm.

List of Avalanche Problems <here>

 

 

TRAVEL ADVISORY: Monitor how the new snow is bonding to old surfaces and have your senses tuned in for whumphing and cracking: signs of slab over weak layers. All of the ingredients are there for an avalanche: a dense slab resting on a slick or weak interface underneath.

As more snow continues to accumulate the next few days, limit your time below steep, rocky terrain: natural, loose avalanches are possible in these areas.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY:

  • Monday Dec 15 about 3pm, a skier triggered D2 windslab slid above the thick melt crust on a short roll-over along the ridge to access Little Girls (about 3900 ft). It sympathetically released another D2 on the next feature over that was slightly larger. Both events occurred in thinly covered, steep, rocky, south facing terrain…..very similar to 2 events below. See Observations Page for more details.
  • On Dec 10 and 11, two remotely released, size 2, windslab avalanches occurred on similar aspects (SSE) and elevation (3000 feet) at Milepost 28 below Catcher Mitt. These happened in steep, rocky and wind loaded areas.
  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Given nearly 10 inches of new snow, consider the variety of firm surfaces and weak layers that can present problems once buried. This new snow has created slabs that are denser and more supportive the higher one travels, due exposure to stronger winds.  The lighter, dryer snow that this new snow sits on can easily be found about 20 cm deep and one can see the layer collapse in compression testing.

Looking deeper into the snowpack on Thompson Pass, buried facets (sugar snow) and ice crusts are leading to easy to moderate test results: failures within weak facets above and below the old crusts. Additionally, easy test results have been noticed in between wind slabs in lee features, very protected from previous NE winds (similar to the recent human triggered avalanches).

Keep in tune with the conditions by continuing to poke around in the snow and share your observations so all can benefit.

WEATHER:  While a mix of rain and snow fall in town and a thin slush layer doesn’t make it feel like true winter, realize that over 9 feet of snow have fallen on Thompson Pass this season and more is on its way.  It looks like more significant snowfall Tuesday evening before drying up and that temperatures will remain consistently below freezing after it cools Wednesday evening.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/16 PM  12/16 AM
Current Snow Depth 5.0″
32″
24 Hour Snow / Water Equiv. 0″ / 0″ 1″ / 0.2″
December Snow / Water Equiv. 22″ / 1.9″ 42″ / 4.1″
Total Winter Snowfall / Water Equiv.
27″ / 4.8″ 111″ / 12.1″
Snowload in Valdez <9.9 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Monday through Thursday December 15-18, 2014

Monday through Thursday December 15-18, 2014               Updated 8AM Dec 15

MONDAY         TUESDAY          OUTLOOK FOR WEDNESDAY & THURSDAY

         

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable and will remain steady as precipitation amounts haven’t been overbearing. Tuesday evening has the potential for a dramatic accumulation that could change Wednesday’s danger.  Look back here for any updates.  Remember, Considerable means that natural avalanches are possible, human triggered avalanches are likely and that dangerous avalanche conditions exist.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are possible on slopes loaded from previous outflow northeasterly winds and more recent onshore southeast winds with this new storm.

Storm Snow Avalanches –  are likely as significant accumulation continues and heavier, wet snow lands on dry. Just below the new dry snow from recent days are buried layers that delay bonding and promote avalanche activity.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Monitor how the new snow is bonding to old surfaces and have your senses tuned in for whumphing and cracking: signs of slab over weak layers. All of the ingredients are there for an avalanche: a dense storm slab resting on a slick or weak interface underneath.

As the storm progresses and accumulation continues, limit your time below steep, rocky terrain: natural, loose avalanches are possible in these areas.

With warm temperatures and rain down at lower elevations, consider wet, loose activity as moisture weighs down and lubricates the snowpack.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY: Roller balls were seen on the pass Sunday, demonstrating the warmth and wetness of the recent snow deposit. This wet, dense snow is resting on dry, weaker from the previous storm.

On Dec 10 and 11, two remotely released, size 2, windslab avalanches occurred on similar aspects (SSE) and elevation (3000 feet) at Milepost 28 below Catcher Mitt (photo below). These happened in steep, rocky and wind loaded areas.

20141210 Remote? Below Catchers Mitt

December 10th Remotely Triggered Avalanche Below Catchers Mitt at Milepost 28

 

 

 

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

 

SNOWPACK DISCUSSION:   Given the all of the new snow, consider the variety of firm surfaces and weak layers that can present problems once buried. This new snow can consolidate and create storm slabs problems, especially if it has a easy surface to run on. The warm temperatures Sunday and possibly Monday, will further complicate things as it creates a wet-heavy layer (possibly combined with rain) on top of previous dry-light deposits. This combination can create dangerous avalanche conditions, so investigate.

Looking deeper into the snowpack on Thompson Pass, buried facets (sugar snow) and ice crusts are leading to easy to moderate test results: failures within weak facets above and below the old crusts, depending on elevation. On the other hand, easy test results have been noticed in between wind slabs in lee features, very protected from previous NE winds (similar to the two recent human triggered avalanches).

Keep in tune by continuing to poke around in the snow and share your observations so all can benefit.

WEATHER:  While a mix of rain and snow fall in town and a thin slush layer doesn’t make it feel like true winter, realize that nearly 9 feet of snow have fallen on Thompson Pass this season and continues to accumulate.  It looks like this precipitation will culminate in a more intense Tuesday evening before letting up and that temperatures will remain consistently below freezing after it cools Wednesday night.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/15 AM  12/15 AM
Current Snow Depth 5.5″
33″
24 Hour Snow / Water Equiv. 0″ / 0″ 9″ / 0.8″
December Snow / Water Equiv. 22″ / 1.9″ 41″ / 3.9″
Total Winter Snowfall / Water Equiv.
27″ / 4.8″ 110″ / 11.9″
Snowload in Valdez <9.9 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Sunday through Wednesday December 14-17, 2014

Sunday through Wednesday December 14-17, 2014               Updated 8AM Dec 14

SUNDAY            MONDAY          OUTLOOK FOR TUESDAY & WEDNESDAY

    high icon     

DANGER SCALE

DANGER TREND: The avalanche danger is Considerable and will increase as winds, continued precipitation and warmer weather moves in. This warmer weather will bring wet snow and rain to settle on top of the very dry/light previous snow, creating an unstable scenario.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are possible on slopes loaded from previous outflow northeasterly winds and more recent onshore southeast winds with this new storm.

Storm Snow Avalanches –  are likely as significant accumulation continues and heavier, wet snow lands on dry. Just below the new dry snow from recent days are buried layers that delay bonding and promote avalanche activity.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Monitor how the new snow is bonding to old surfaces and have your senses tuned in for whumphing and cracking: signs of slab over weak layers.

As the storm progresses and accumulation continues, limit your time below steep, rocky terrain: natural, dry, loose avalanches are possible in these areas.

With warm temperatures and rain down at lower elevations, consider wet, loose activity as moisture weighs down and lubricates the snowpack.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY:  On Dec 10 and 11, two remotely released, size 2, windslab avalanches occurred on similar aspects (SSE) and elevation (3000 feet) at Milepost 28 below Catcher Mitt (photo below). These happened in steep, rocky and wind loaded areas.

20141210 Remote? Below Catchers Mitt

December 10th Remotely Triggered Avalanche Below Catchers Mitt at Milepost 28

 

 

 

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

 

SNOWPACK DISCUSSION:   Given the all of the new snow on its way, consider the variety of firm surfaces and weak layers that could present future problems once buried. This new snow could build up and create storm slabs, especially if it has a easy surface to run on. The warming temperatures will further complicate things as it creates a wet-heavy layer (possibly combined with rain) on top of previous dry-light deposits.

Looking deeper in the snowpack on Thompson Pass, buried facets (sugar snow) and ice crusts are leading to easy to moderate test results (failures on facets above and below the mid Nov crust, depending on elevation) while easy test results have been noticed in between wind slabs in very protected, south-facing features from previous NE winds (similar to the two recent human triggered avalanches).

Keep in tune by continuing to poke around in the snow and share your observations so all can benefit.

WEATHER:  Thompson Pass has received 105 inches of snowfall this winter and new snow continues to accumulate. While a mix of rain and snow so will fall in town, Thompson Pass will see significant accumulation which began last night. This new wave of precipitation is coming in warmer, and there is even a chance of rain at Thompson Pass. It looks like things will cool back off, and Thompson Pass could see up to 20 inches by Wednesday.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/14 AM  12/14 AM
Current Snow Depth 10″
32″
24 Hour Snow / Water Equiv. 0.2″ / .02″ 5″ / 0.5″
December Snow / Water Equiv. 22″ / 1.9″ 36″ / 3.4″
Total Winter Snowfall / Water Equiv.
27″ / 4.8″ 105″ / 11.4″
Snowload in Valdez 9.9 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Saturday through Tuesday December 13-16, 2014

Saturday through Tuesday December 13-16, 2014               Updated 8AM Dec 13

SATURDAY            SUNDAY          OUTLOOK FOR MONDAY & TUESDAY

Considerable

Considerable   high icon

DANGER SCALE

DANGER TREND: The avalanche danger is CONSIDERABLE and will increase as significant precipitation moves into the area. The danger will vary depending on the precipitation amounts and winds of the upcoming storm.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are expected on slopes loaded from previous outflow northeasterly winds and more recent onshore southeast winds with this new storm.

Storm Snow Avalanches –  are possible if significant accumulation continues. Depending on the area, this new snow will be resting on some weak surface hoar, a thin melt freeze crust and/or rigid wind slab. All of these now buried layers could delay bonding and promote avalanche activity.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Monitor how the new snow is bonding to old surfaces and have your senses tuned in for whumphing and cracking: signs of slab over weak layers.

As the storm progresses and accumulation continues, limit your time below steep, rocky terrain: natural, dry, loose avalanches are possible in these areas.

With warm temperatures and rain down at lower elevations, consider wet, loose activity as moisture weighs down and lubricates the snowpack.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY:  On Dec 10 and 11, two remotely released, size 2, windslab avalanches occurred on similar aspects (SSE) and elevation (3000 feet) at Milepost 28 below Catcher Mitt (photo below). These happened in steep, rocky and wind loaded areas.

20141210 Remote? Below Catchers Mitt

December 10th Remotely Triggered Avalanche Below Catchers Mitt at Milepost 28

 

 

 

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Thompson Pass has received 100 inches of snowfall this winter. As new snow accumulates in town and up at Thompson Pass, consider the variety of firm surfaces and the notoriously weak surface hoar layer that could present future problems after buried. This new snow could build up and create dangerous storm slabs, especially if it has a easy surface to run on.

At Thompson Pass the buried facets (sugar snow) and firm crusts are leading to moderate test results (failures on facets above and below the mid Nov crust, depending on elevation) while easy test results have been noticed in between wind slabs in very protected lee features (similar to the two recent human triggered avalanches).

Keep in tune by continuing to poke around in the snow and share your observations so all can benefit.

WEATHER:  As the low pressure south of us moves east, it will bring increasing amounts of precipitation through the weekend and into next week. Expect a few more inches Saturday. Rising temperatures may result in rain at the lower elevations.  It looks like the precipitation intensity will increase over the weekend and continue into Monday or even Tuesday.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/13 AM  12/13 AM
Current Snow Depth 10″
28″
24 Hour Snow / Water Equiv. 4.3″ / .2″ 2″ / 0.05″
December Snow / Water Equiv. 22″ / 1.9″ 31″ / 2.9″
Total Winter Snowfall / Water Equiv.
27″ / 4.8″ 100″ / 10.9″
Snowload in Valdez 9.9 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Friday through Monday December 12-15, 2014

Friday through Monday December 12-15, 2014               Updated 8AM December 12

FRIDAY            SATURDAY          OUTLOOK FOR SUNDAY & MONDAY

Considerable

Considerable   high icon

DANGER SCALE

 

DANGER TREND: The avalanche danger is CONSIDERABLE and will increase as significant precipitation moves into the area Sunday. The danger could vary depending on the true intensity of the upcoming storm.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are expected on slopes loaded with the outflow northeasterly winds.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Human triggered avalanches are still happening and expected. Whumphing and cracking are signs of slab over weak layers, yet some remotely triggered slabs haven’t shared these red flags before release. See the refreshingly candid self-evaluation of last weekend’s tragedy <here> and carefully weigh up the consequences of the terrain you plan to travel across.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

20141211_122813

 

December 10th Remotely Triggered Avalanche

AVALANCHE ACTIVITY:  On Dec 10 and 11, two remotely released, size 2, windslab avalanches occurred on similar aspects (SSE) and elevation (3000 feet) at Milepost 28 below Catcher Mitt (photo above). These happened in steep, rocky and wind loaded areas.

Numerous dry, loose snow activity from steep, rocky terrain during the most recent storm.

Widespread moist snow point releases off all aspects to size 2 December 8 along the Lowe River valley and above town and out the Port in the maritime snow climate zone.

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   With up to two feet of new snow since the weekend and moderate NE winds, windslabs have formed throughout the terrain. These slabs have demonstrated to be incredibly sensitive in steep, rocky areas with significant loading. The recent clear, cold nights have helped to start the growth of surface hoar on top of a very thin rime crust. Watch how these layers interact with the new snow that lays on top of it.

On all aspects on Thompson Pass, facets just below crusts in the midpack and down closer to the ground are still weak and could cause some future problems.

WEATHER:  Light snow will move in Friday and increase Saturday afternoon before turning into a significant storm by Sunday. This weather will bring stronger winds reaching the upper 20’s for Thompson Pass.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/12 AM  12/12 AM
Current Snow Depth 4″
28″
24 Hour Snow / Water Equiv. 0″ / 0″ 0″ / 0″
December Snow / Water Equiv. 17.7″ / 1.7″ 29″ / 2.85″
Total Winter Snowfall / Water Equiv.
22.75″ / 4.6″ 98″ / 10.85″
Snowload in Valdez 8.8 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Thursday through Sunday, December 11-14, 2015

Thursday through Sunday December 11-14, 2014               Updated 8AM December 11

THURSDAY            FRIDAY          OUTLOOK FOR SATURDAY & SUNDAY

Considerable

Considerable   

DANGER SCALE

 

DANGER TREND: The avalanche danger is CONSIDERABLE. The danger will remain steady throughout the weekend. The danger may increase should the next storm develop more intensely than presently forecast.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are expected on slopes loaded with the outflow northeasterly winds.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Human triggered avalanches are still expected. Whumphing and cracking are signs of slab over weak layers. See the refreshingly candid self-evaluation of last weekend’s tragedy <here> and carefully weigh up the consequences of the terrain you plan to travel across.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. Develop snow analysis skills at the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY:  On December 10 at Milepost 28 a size 2 windslab released (possibly skier triggered or remote triggered) from 3500 feet elevation off a south aspect below Catcher Mitt. (Thanks Derek, Sean and JP)

Widespread moist snow point releases off all aspects to size 2 December 8 along the Lowe River valley and above town and out the Port in the maritime snow climate zone. Whumphing and cracking Dec.7 in Nick’s Happy Valley. (See observation page.)

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Up to two feet of soft snow has accumulated since the weekend. The new snow is drifted into easily triggered soft windslabs on wind affected terrain. The cooler temperature prior to this last storm created weak faceted sugar snow both over and within the now buried old snow.

WEATHER:  Sunny Thursday followed with flurries Friday and Saturday developing into real accumulation of up to 8 more inches by the middle of next week. Although the forecast winds look to be a mixture of over-riding onshore southerlies squeezing out outflow northerlies through the mountain passes and river valleys, what will increase avalanche danger is the forecast above sea-level freezing levels and rain in the lower elevations Sunday through Tuesday.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/11 AM  12/11 AM
Current Snow Depth 4″
28″
24 Hour Snow / Water Equiv. 0″ / 0″ 0″ / 0″
December Snow / Water Equiv. 17.7″ / 1.7″ 29″ / 2.85″
Total Winter Snowfall / Water Equiv.
22.75″ / 4.6″ 98″ / 10.85″
Snowload in Valdez 9.8 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours

Tuesday through Friday, December 9-12, 2014

Tuesday through Friday December 9-12, 2014               Updated 8AM December 10

TUESDAY            WEDNESDAY          OUTLOOK FOR THURSDAY & FRIDAY

Considerable

Considerable   

DANGER SCALE

 

DANGER TREND: The avalanche danger is CONSIDERABLE. The danger is steady until evidence of strengthening bonding between the recent new snow and the old snow beneath.

AVALANCHE PROBLEM:

Wind-Slab iconWind Slab Avalanches –  are expected both on slopes loaded in the maritime snow climate zone with the onshore southerly flow as well as those slopes loaded with the outflow northeasterly winds of the past few days.

List of Avalanche Problems <here>

TRAVEL ADVISORY: Human triggered avalanches are still expected. Whumphing and cracking are signs of slab over weak layers. Evaluate the consequences of the terrain you plan to travel across.

If you want to learn about more about recognizing avalanche terrain and decision making, consider taking an Avalanche class: Level 1 January 9-11, 2015. To further your snow analysis skills, consider the Avalanche Level 2 March 6-9, 2015.

AVALANCHE ACTIVITY:  On December 10 at Milepost 28 a size 2 windslab released (possibly skier triggered or remote triggered) from 3500 feet elevation off a south aspect below Catcher Mitt. (Thanks Derek, Sean and JP)

Widespread moist snow point releases off all aspects to size 2 December 8 along the Lowe River valley and above town and out the Port in the maritime snow climate zone. Whumphing and cracking Dec.7 in Nick’s Happy Valley. (See observation page.)

  • Avalanche sizing using the destructive scale <here>
  • Avalanche size estimation aid <here>.

SNOWPACK DISCUSSION:   Up to two feet of soft snow has accumulated since the weekend. The new snow is drifted into easily triggered soft windslabs on wind affected terrain. The cooler temperature prior to this last storm created weak faceted sugar snow both over and within the now buried old snow.

WEATHER:  Flurries drying out Wednesday and becoming sunny Thursday and into Friday before the clouds return with the onset of next weekend’s snowfall. Winds are not expected to be our normal post weather northerly outflow screamers.

Use links below to follow the up and coming weather.

SNOW & PRECIPITATION HISTORY:
VALDEZ
THOMPSON PASS
 Updated  12/10 AM  12/10 AM
Current Snow Depth 4″
29″
24 Hour Snow / Water Equiv. 0″ / 0″ 2″ / 0.2″
December Snow / Water Equiv. 33.5″ / 2.25″ 29″ / 2.85″
Total Winter Snowfall / Water Equiv.
28.5″ / 5.15″ 98″ / 10.85″
Snowload in Valdez 3 lbs / square foot
Snow Depths and Water Equivalents: date depth snow water equivalent
Valdez Ball Fields (Wood Way)  12/10  6  1.1
Milepost 18  12/10  14  2.4
Worthington Glacier air strip 12/8 32” 5.3”
Milepost 37 Tsaina River bridge 12/8 24” 4.4”

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>.
  • Thompson Pass weather <here>.
  • Further weather resources <here>

Our region is “one of the snowiest places on earth” says the recent weather detective climatologist investigation into the Serendipity / Rendezvous snowfall record set in 1963 <here>.

SNOW CLIMATE ZONES:

  • Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Elevations:
  • Upper Elevations: Alpine – Above 2,000 feet
  • Mid Elevations: Treeline – 2,000 feet
  • Lower Elevations: Below treeline – Below 2,000 feet

 

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Like warm milk, this forecast expires after 24 hours