Valdez

Forecast Expired

Above 4,000ftConsiderable

2,000 to 4,000ftConsiderable

Below 2,000ftLow

Degrees of Avalanche Danger

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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

Storm Snow:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Deep Slab:

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

Limited visibility prevented observation of natural avalanche activity that occurred through the New Years Eve storm.  Naturals were observed in multiple paths on 40.5 mile and Three Pigs.

12/31 Numerous small-medium natural avalanches observed below 4000′ on steep rollovers on the north side of the pass.

12/30  Natural avalanche observed on Cracked Ice Butress at 2700′.  300 meters wide~, 1 meter+ deep~.  Connected through gullies and over ridges.

D3 avalanche on east face of Mt. Tiekel mp 50 ran into top 1/3 of apron..

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

1/3: There is a high pressure system establishing itself over mainland Alaska, and a low pressure system will move across the Gulf. This pressure difference will cause north winds to become strong today through Sunday. This will also cause very cold air to be pulled from interior locations into our area. There is a wind chill advisory in effect for Thompson Pass beginning tonight that will produce dangerous wind chill values of -50 F.

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`      11 F         -5 to 1 F

Temp at 3000`      -3 to 3 F    0 F

Chance of precip   0%           0%

Precip amount
(above 1000 FT)    0.00 in      0.00 in

Snow amount
(above 1000 FT)    0 in         0 in

Snow level         sea level    sea level

Wind 3000` ridges  NE 10-30 mph NE 15-36 mph

Remarks...Wind Chill Advisory in effect from midnight tonight until
9 AM Sunday.
  24h snowfall (inches) HN24W (inches)* Hi Temp (F) Low Temp (F) January snowfall Season Snowfall Snow height 
Valdez Trace   22 2 3 74 32
46 mile 0 0 18 -8 12

Nicks Snotel “4500′”

0 10 1 130

 HN24W= total water received last 24 hours in inches

Additional Information

We are on the tail end of a major series of storms.  The snowpack is gaining strength with falling temperatures and the end of precipitation.  BUT…. We have a problem layer that is now buried deep within the snowpack.  This poses multiple problems that may make decision making difficult.  Since this layer is buried deeply, it may not show the signs of instability- shooting cracks, collapsing.  Also, it may allow multiple people to ski or snowmachine on a slope before someone finally finds the sweet spot and triggers an avalanche.  This type of avalanche will be most likely triggered from areas where the slab is thinner and the weak layer is closer to the surface, near rock outcroppings, or other thin areas of the snowpack.  

North east winds are forecasted to ramp up today and will create instabilities near the surface on lee slopes (SE-NW).  Avoid areas that have fresh wind slab and slopes that are receiving active wind loading.  Human triggered avalanches will be likely in these areas and could step down into deeper layers of the snowpack creating very large avalanches.

 The new snow has opened up different access points.  Use caution as you step forward into new zones.  New snow combined with strong winds from different directions has created a lot of spatial variability in our area.  Careful snowpack evaluation and conservative terrain choices will be critical today.  The hazard will slowly decrease with time.

 

 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

Announcements

The avalanche hazard is considerable at mid and upper elevations.  Human triggered avalanches are likely.  Thompson Pass has received 10 feet of snow since 12/22, combined with strong winds.     The snowpack will need time to adjust to this new snow.  Avoid large avalanche paths, steep slopes and terrain traps.