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Avalanche Forecast

Apr 9th, 2021–Apr 10th, 2021
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
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
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Lizard-Flathead.

New snow and wind are expected to increase the avalanche danger at upper elevations. Watch for areas of wind-drifted snow, especially near ridge-crests, roll-overs, and in steep terrain, and minimize your exposure to cornices. 

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Friday night: Cloudy, 5-10 cm of snow, moderate southwest wind with strong gusts at ridgetops, treeline temperatures near -6 C, freezing level dropping to 1200 m.

Saturday: Cloudy, 5-10 cm of snow, light southwest wind, treeline temperatures near -5 C, freezing level rising to 1400 m and dropping to valley bottom overnight.

Sunday: Sunny with afternoon cloud, light variable wind, treeline temperatures near -2 C, freezing level rising to 1700 m and dropping to valley bottom overnight.

Monday: Mix of sun and cloud, light northeast wind, treeline temperatures near -4 C, freezing level rising to 1500 m and dropping to valley bottom overnight. 

Avalanche Summary

On Thursday, there were reports of several small (up to size 1.5) loose dry avalanches.

Snowpack Summary

Another 10-20 cm of new snow is forecast to accumulate by midday Saturday with moderate southwest wind. The new snow will combine with the previous 10-20 cm of snow from earlier in the week, continuing to build fresh wind slabs in lee features that may be possible to human trigger. Cornices are large, looming, and capable of triggering avalanches when they fail.

The mid-pack is firm and well settled. Some faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack. Snow line is slowly creeping up the mountains to roughly 1400 m in elevation. Check out this MIN report for more details on the access from common staging areas.

Glide cracks releasing as full depth glide slab avalanches become more common in the spring and are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid freshly wind loaded terrain features.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.

Avalanche Problems

Wind Slabs

Recent snow and wind are expected to form fresh wind slabs that may be reactive to human triggering.   

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1.5 - 2.5

Cornices

Cornices are large and looming along many ridgelines. They are capable of triggering large avalanches when they fail.

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1.5 - 2.5