Lizard Range and Flathead Avalanche Forecast

Issued: Apr 9th, 2021 4:00PM

Sat Apr 10th Current Conditions
Alpine Considerable Treeline Moderate Below Treeline Low
Sun Apr 11th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Low
Mon Apr 12th 3 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Low

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Cornices.

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. 

Summary

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.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible-Likely

Expected Size

1.5 - 2.5

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.

Cornices

An icon showing Cornices

Likelihood

Possible

Expected Size

1.5 - 2.5

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.

Valid until: Apr 10th, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.