Valdez

Forecast Expired

Above 3,000ftModerate

1,500 to 3,000ftModerate

Below 1,500ftModerate

Degrees of Avalanche Danger

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Avalanche Problems

Problem 1

Persistent Slab:

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Wind Slab:

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Storm Snow:

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

2/2: Numerous Small pockets of unsupported terrain released naturally in the tsaina valley 2′ deep.

1/27-1/30: Naturals were observed on RFS, N aspect ~6000′,

Avalanches were also observed on -40.5 mile, ~5000′ ,W aspect, 60 m crown

– 2 paths on Three Pigs, ~5000′, SE aspect, ran into the top 1/3 of aprons.

– 3 slides on Billy Mitchell ranging from 3000′-6000′, NW- N aspect.  The most significant was on the upper bowl of cry babys, ~5000′, ~200 m crown, 1-2 meters deep.  

1/23- Found fresh debris in a gully off point 3848′ behind the airport.  D2, ran ~2000′.

~ 1/10- There have been several natural windslabs that have released in the Thompson Pass region:

-South slope of catchers mitt, near 27 mile icefall,~3500′, ~300m wide ,~3′ deep, ran 500′ HS-N-R3-D2.5.  Photo shows extent of crown, which may have been bigger and is now filled in by wind transported snow.

– Gully Between Little and Big Oddessey, NW, 4000′, ~60 M wide, ~2-4′ crown, ran 1000′

-Averys, ~4000′, SW, ~70 M wide, ran ~1000′

1/11- Two natural wind slab avalanches observed at moonlight basin, 2500′-2800′, S aspect.  

The first was on the small last roll before the road and had debris chunks up to 3′ deep “crown filled in by wind”, 200′ wide.

The second was in a cross loaded gully ~ 300′ above the road, with a crown up to ~10′ deep, ~100′ wide.

 

 

Weather

2/05-  Light snowfall will continue for our area with rain likely along the coast.  Winds are forecasted to be light to moderate out of the SE and temperatures in the mid 20’s for Thompson Pass.

The Thompson Pass Mountain Forecast covers the mountains (above
1000 ft) surrounding Keystone Canyon through Thompson Pass to
Worthington Glacier.

This forecast is for use in snow safety activities and emergency
management.

                   Today        Tonight

Temp at 1000`      33 F         28 F

Temp at 3000`      26-30 F      28 F

Chance of precip   90%          90%

Precip amount
(above 1000 FT)    0.22 in      0.32 in

Snow amount
(above 1000 FT)    2-4 in       3-5 in

Snow level         700 ft       400 ft

Wind 3000` ridges  E 5-25 mph   S 5-15 mph

Remarks...None.
  24h snowfall (inches) HN24W (inches)* Hi Temp (F) Low Temp (F) February snowfall Season Snowfall Snow height 
Valdez 1 .1 30 25 6 113 42
46 mile 2.5 .2 20 13 7 68 25

Thompson Pass “DOT”

4 .23 29 12 12 370 81

 HN24W= total water received last 24 hours in inches

Thompson Pass weather history 19/20 season beginning 12/21 through 1/23.  Click on links below to see full size image.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TP DEC 19

TP Jan through 1/30

 

Additional Information

Prolonged arctic temperatures in January have created a weak snowpack.  Weaknesses in our snowpack are pronounced at old rain crusts where moisture was once concentrated, and has now formed facets.

The upper snowpack will be undergoing a significant change this week.  Snowpacks do not like big changes especially weak ones.  Temperatures will rise to above freezing at sea level for the first time in over a month.  This will cause the upper part of the snowpack to become top heavy.  This will cause additional stress to faceted layers that may become more reactive this week, it is possible we will have a natural avalanche cycle if we see a continued rise in temperatures along with significant precipitation.

Careful snowpack assessment will be essential this week.

Forecast Confidence is LOW.

 

Near surface facets found at 3000′ on Billy Mitchell 1/19. 2 MM grid.

 There have been limited observations from interior locations due to low snow at lower elevations.   Use caution if you travel in these areas.

If you see something in the mountains that could contribute to this forecast, leave a public observation.  The more observations we receive, the better we can tune our forecast. If you would rather not post an observation publicly feel free to send me an email at [email protected]

Be aware that the elevation bands have changed on our website.  Low is now below 2000′, Mid is 2000-4000′ and high is 4000′ and above. 

 

 

 

Announcements

The avalanche hazard is moderate at all elevations.  Warming temperatures and light snowfall is beginning to create a top heavy snowpack.  With continued warm temperatures and snowfall, stress is slowly being added to a weak snowpack and will cause the hazard to increase through the week. Human triggered avalanches are possible today.  Avoid travel in or below large avalanche paths and terrain traps.