Avalog Join
Archived

Avalanche Forecast

Jan 20th, 2024–Jan 21st, 2024
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Fresh wind slabs at higher elevations can be found on all aspects. Expect as temperatures warm, that human triggered avalanches will become likely.

Confidence

Moderate

Avalanche Summary

On Friday explosive testing and control work continued and produced many large to very large avalanches. These avalanches where both wind slab and a very large a deep persistent avalanche. On Thursday explosive avalanche control missions triggered a very large avalanche size 3.5. This avalanche failed on the deep persistent slab layer.

If you go out in the backcountry, please consider sharing your observations on the Mountain Information Network (MIN).

Snowpack Summary

5-10 cm of low density new snow is sitting on weak faceted snow in many areas. In exposed terrain at treeline and above, this new snow is now obscuring old wind slabs.

The mid and lower snowpack is generally weak with several layers of note. Of greatest concern are weak facets and/or depth hoar located at the bottom of the snowpack, particularly in alpine terrain.

Snowpack depths at treeline range from 70 to 160 cm.

Weather Summary

Saturday Night

Mainly cloudy with isolated flurries, 1-2 cm of snow, southeast ridgetop wind 10 to 20 km/h, treeline temperature -12 °C.

Sunday

Mainly cloudy with flurries, 2-4 cm of snow, southeast ridgetop wind 10 to 20 km/h, treeline temperature -9 °C.

Monday

Mainly cloudy with isolated flurries, 1-2 cm of snow, southeast ridgetop wind 10 to 20 km/h, treeline temperature -6 °C.

Tuesday

Mainly cloudy with isolated flurries, 1-2 cm of snow, southeast ridgetop wind 10 to 15 km/h, treeline temperature -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.

Avalanche Problems

Wind Slabs

Wind slabs may be more reactive where they sit on a weak layer of facets. Expect slab sensitivity to triggering and reactivity to increase as temperatures warm.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Deep Persistent Slabs

There is a weak layer of facets and depth hoar near the base of the snowpack in most alpine areas. The likelihood of triggering a deep persistent slab is low, however the consequence of doing so is high.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely - Possible

Expected Size: 1.5 - 3.5