Valdez

Forecast Expired

Above 3,000ftModerate

1,500 to 3,000ftLow

Below 1,500ftLow

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Glide Avalanches:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

 12/10-The only new natural avalanche activity in the Thompson Pass corridor was small, wet point-releases off the Nicks and Python Buttresses.  These originated from 3500-4000′ and did not entrain more snow.

12/8-  An observer witnessed a glide crack avalanche.  SW aspect of peak 4690′ above the Valdez Glacier Lake. The debris reportedly ran all the way to the lake, with the deposition pile only feet away from a well used cross country ski trail.

Weather

Friday is forecasted for light snow with an inch or two of accumulation expected.  Winds will be moderate out of the East. Highs 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`      34 F         29 F

Temp at 3000`      24-32 F      27 F

Chance of precip   80%          90%

Precip amount
(above 1000 FT)    0.07 in      0.32 in

Snow amount
(above 1000 FT)    0-1 in       2-5 in

Snow level         800 ft       sea level

Wind 3000` ridges  E 12-28 mph  E 8-23 mph
  24h snowfall (inches) HN24W (inches)* Hi Temp (F) Low Temp (F) Dec snowfall Season Snowfall
Valdez 0 0 37 30 7 31
46 mile 0 0 21 17

Nicks snotel

(4500′)

0 0 31 26

 HN24W= total water received last 24 hours in inches

Additional Information

Winds have shifted from onshore S/SE to offshore N/NE within the last 48 hours. This switch in wind direction will begin to load South facing slopes below ridge lines with fresh wind slab in locations that receive moderate to strong wind. 12/11 found 2 feet of 4-finger density windslab forming in specific locations. This new slab was cracking underfoot which is a sign that it has energy to slide and will need time to strengthen. Look for these slabs to grow in size if winds become stronger than forecasted or become widespread. Flagging on peaks and ridges will be a sure sign that windslab is building. In places that were unaffected by the wind, the new snow from 12/6-10 is bonding well to the old snow interface. 

 Below 3000′ there is a pencil hard rain crust and good stability.

  If you venture into avalanche terrain today, use terrain progression as a tool.  Start with small slopes that have no consequence, before committing to larger slopes.

If you travel in the mountains today, please leave a public observation.  The more info we can get from various locations will help us to get a clearer picture of the snowpack in our beautiful Valdez Chugach! 

Forecast Confidence is moderate.

Announcements

The avalanche hazard is moderate at upper elevations. Natural avalanches are unlikely today unless caused by a glide crack. Skier triggered  avalanches are possible on  steep terrain, or in areas that have been affected by north winds. Good indicators for windslab are a rapid increase in depth of the new snow over a short distance, shooting cracks and a hollow, drum-like feel. Use caution in the mountains today, watch for windslab and avoid terrain traps.