Forecast as of 12/15/2018 at 08:00 and expires on 12/16/2018

Above 3,000ftConsiderable

1,500 to 3,000ftConsiderable

Below 1,500ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem Details


The avalanche danger is CONSIDERABLE above 1500' or where there is enough snow to slide, which could be as low as 500'. OVER 12" of new snow covered most of the Valdez region in the last 24 hours with a few hours of 2" of snow per hour. This new snow is sitting on widely variable snowpacks that have complicated layers including facet-crust combos and basel facets. With a forecasted break today for decent visibility the temptation to 'get after it' will be strong but careful route finding, snowpack assessment, and team dynamics are essential to LIVE TO RIDE ANOTHER DAY!


Problem 1: Storm Snow. 

Chance: Likely. Size: Small to Large. Location: All aspects. All elevations.

45" of new snow has fallen on Thompson Pass since Dec 8th, snowing everyday, including at least 12" in the last 24 hrs. Expect small to large slab avalanches up to 3' deep on slopes 30deg or steeper. These new soft slabs could be easy to trigger: TOUCHY. There has been little wind but on near ridgelines or exposed areas wind loading could easily have doubled the recent 12" into 24" deep pockets. Avoid loaded slopes particularly just below ridgeline.


Problem 2: Persistent Slab.

Chance: Possible. Size: Large. Location: All aspects above 1500'.

There are multiple buried problem layers on ALL aspects and most elevations. There are multiple facet-crust combos buried anywhere from 1-6' deep and also basel facets (bottom of snowpack, weak, sugar snow, up to 3mm). Stability tests have shown inconsistent results ranging from very reactive to unreactive (dormant). These layers are all showing signs of gaining strength (rounding grains) but our confidence is low of how these layers will react to large loads: more snow, skiers, and snow machines. The probability of triggering a deep slab avalanche on one of these layers is low but the consequence would be high!


Problem 3: Dry Loose.

Chance: Likely. Size: Small. Location: All aspects. All Elevations.

Where the new snow is not wind affected DRY LOOSE sloughs could easily be large enough to knock over and bury a rider. Dry loose avalanches often entrain more and more snow on their way down the mountain. Be mindful of your group spacing and what terrain traps and/or cliffs are below you. Watch your SLUFF.

Avalanche Activity

Over the past week there have been several slab avalanches on multiple aspects at different elevations up to size 2 including a slide last Saturday that covered the road with debris. There have been limited field observations to validate the type, trigger, or other details of these slides however; we believe they are mostly within the new snow or high in the snowpack at the new/old snow interface.

Please share field observations and photos as you get out into the field.


From the National Weather Service Rec Forecast:

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

                   Today        Tonight

Temp at 1000`      24 F         20 F

Temp at 3000`      19-28 F      16-23 F

Chance of precip   0%           80%

Precip amount
(above 1000 FT)    0.00 in      0.12 in

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

Snow level         sea level    sea level

Wind 3000` ridges  NE 15-29 mph NE 18-36 mph


Additional Information

If you get out riding, please send in an observation!

Start the season with fresh batteries in your beacon, and do a rescue practice with your partners. Always carry a beacon, shovel, and probe, and KNOW HOW TO USE THEM.

Practice good risk management, which means only expose one person at a time to slopes 30 degrees and steeper, make group communication and unanimous decision-making a priority, and choose your terrain wisely: eliminating unnecessary exposure and planning out your safe zones and escape routes.

Do you have the right route, the right group, the right skills on the right day?

Live to Ride Another Day!


The avalanche danger is CONSIDERABLE above 1500' due to high volume of recent snow and complicated problem layers in the snowpack. Early season conditions: low snowpack with widespread variability. Use caution as you enter avalanche terrain (slopes over 30deg) and be aware that avalanche terrain may be ABOVE you. Areas of thinner snowpack are more suspect for weaker and unstable snow especially further inland and north of 32 mile. We have seen a lot of recent snow, in a short amount of time, and have limited snowpack data!