Archived

Avalanche Forecast

Feb 17th, 2022–Feb 18th, 2022

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Northwest Inland.

New snow and wind are forming fresh slabs over a slippery crust. Avoid freshly wind loaded terrain features and watch for signs of instability like cracking or recent avalanches.

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

Thursday night: Flurries around 5 cm, strong northwest wind, freezing level 1200 m.

Friday: Flurries 5-10 cm, strong southwest wind, high of +1, freezing level 1200 m.

Saturday: Flurries 5-10 cm overnight then easing, moderate west wind, high of -2, freezing level 800 m.

Sunday: A mix of sun and cloud, light northwest wind, high of -4, freezing level valley bottom.

Avalanche Summary

Several skier triggered size 1 wind slabs were reported on Tuesday and Wednesday. The size and distribution of the slabs are expected to increase as snow accumulates.

Snowpack Summary

Incremental inputs of new snow are being loaded into leeward terrain features by strong wind. These fresh wind slabs sit over a thick rain crust. The 10-20 cm thick rain crust makes human triggering of avalanches on weak layers deeper in the snowpack very unlikely.

Cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures can trigger very large persistent slab avalanches that would otherwise be difficult to human trigger.

Terrain and Travel

Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
Wind slabs may be poorly bonded to the underlying crust.
Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.

Avalanche Problems

Wind Slabs

Incremental inputs of new snow accompanied by strong wind continue to form fresh wind slabs on lee features at treeline and above.

Cornices overhead are a primary concern during sunny, warm, or windy conditions. Cornice failures may trigger large persistent slab avalanches that would otherwise be difficult to trigger.

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 1.5