Valdez

Forecast Expired

Above 3,000ftHigh

1,500 to 3,000ftHigh

Below 1,500ftConsiderable

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Storm Snow:

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

Wind Slab:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

12/28- Several natural avalanches reported in the 54 mile area near brush line.  100′ wide and ran 300′.  Depth was not observed.

12/26- Skier triggered avalanche on Cracked Ice Buttress: N aspect, 2500′, 37° slope, 18 inches deep, 100 feet wide, ran 200-300 feet. SS-ASu-D1-R1-I

12/24- Skier triggered avalanche on Python Buttress: NW aspect, 2700′, 35° slope, 60 feet wide, ran 200-300 feet.  SS-ASu-D1.5-R1-O

12/18- A large glide release was reported off Snowslide Gulch middle peak size 2.5.

12/15- Observed small natural avalanche on west aspect of Goodwills.   Released below a cliff band at the bottom of a slope, 100′ wide.   SS-N-D1-N

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

12/29  We are expecting an additional foot of snow today through tonight on Thompson Pass. Winds are forecast to be moderate out of the south and temperatures in the upper 20’s.

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`      30 F         29 F

Temp at 3000`      28 F         27 F

Chance of precip   100%         100%

Precip amount
(above 1000 FT)    0.52 in      1.03 in

Snow amount
(above 1000 FT)    4-8 in       6-12 in

Snow level         sea level    sea level

Wind 3000` ridges  S 4-13 mph   E 6-27 mph
 
  24h snowfall (inches) HN24W (inches)* Hi Temp (F) Low Temp (F) Dec snowfall Season Snowfall Snow height 
Valdez 9 .6 33 15 47 64 35
46 mile 8 .5 5 0 20

Thompson Pass “DOT”

10-12 “6pm-6am” 23 -3

 HN24W= total water received last 24 hours in inches

Additional Information

Below 4000′ we are developing the perfect recipe for avalanches: a bed surface, a weak layer and a slab.  The 12/9 rain crust will act as our bed surface.  Above the rain crust is our weak layer, a 5 cm layer of facets that has been created by the recent cold weather. Third is our slab, which has been created by snowfall that started 12/22 and is approaching  5′ at Thompson Pass.  This slab is growing in size with heavy snow forecasted through the weekend.  If we receive more significant snowfall, it is possible that the weak layer will be overcome by the weight of the new snow and we will see a natural avalanche cycle.  Rising temperatures the night of 12/28 will make avalanches more likely. Hazard will remain High until significant snowfall stops.

Above 4000′ forecast confidence is low.

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 have traveled in the mountains, 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.

Video taken 12/20 in the Mt. Dimond area showing reactive test slopes.   https://vimeo.com/user106668057/review/380916811/02da5d1cc7

Alerts

The avalanche hazard is High today at mid and upper elevations on all aspects.  Natural avalanches are likely and human triggered avalanches are very likely.  Thompson Pass has received 5 feet of snow in the last week accompanied by strong wind.  Avoid travel in avalanche terrain today.  Stay clear of avalanche runout zones.  The hazard will remain elevated with more heavy snow in the forecast.