Lizard Range and Flathead Avalanche Forecast

Issued: Apr 20th, 2021 4:00PM

Wed Apr 21st Current Conditions
Alpine Moderate Treeline Moderate Below Treeline Moderate
Thu Apr 22nd 2 Day Outlook
Alpine Considerable Treeline Moderate Below Treeline Moderate
Fri Apr 23rd 3 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Low

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Loose Wet and Cornices.

One more day of warm sunny weather before the next snowfall arrives. Avoid sun-exposed slopes and cornices at peak midday warming on Wednesday. 

Summary

Confidence

Moderate - Uncertainty is due to difficult to forecast freezing levels.

Weather Forecast

Tuesday night: Clear, light winds becoming west, alpine temperature -4 C, freezing level dropping to valley bottom. 

Wednesday: Sunny, light northwest winds, alpine high temperature -1 C, freezing level 2600 m. 

Thursday: Cloudy, 10-20 cm of snow, light northeast wind with moderate ridgetop gusts, alpine high temperature near 0 C and dropping through the day, freezing level dropping to valley bottom.

Friday: Mainly cloudy, light wind becoming southwest, alpine high temperature -3 C, freezing level rising to 1800 m. 

Avalanche Summary

Over the past several days with sunny weather, there have been reports of natural wet loose avalanches ranging from size 1-2.5. 

Snowpack Summary

Sunny weather is forecast to stick around for Wednesday, which may initiate wet loose avalanches as the snow loses cohesion. Cornices are large and looming along ridgelines. Sun and warm temperatures will increase the chances of cornice failures, which could trigger avalanches on the slopes below. Check out the Forecaster's Blog for information on how to manage these spring conditions. 

The snowpack is overall strong and settled in most areas. However, steep and rocky alpine slopes with a shallow or thin to thick snowpack may still harbor deeply buried weak layers. 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.

The snow line is slowly creeping up the mountains, making some access areas snow-free. 

Terrain and Travel

  • Extra caution is needed around cornices under the current conditions.
  • Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Stay off recently wind loaded slopes until they have had a chance to stabilize.

Problems

Loose Wet

An icon showing Loose Wet

Likelihood

Possible-Likely

Expected Size

1 - 2

Expect wet loose avalanches to run naturally when steep slopes are exposed to the sun. Activity will start on east-facing slopes in the morning, south-facing slopes throughout the day, and continue on west-facing slopes into the evening. 

Aspects:

East, South East, South, South West, West.

Elevations:

All elevations.

Cornices

An icon showing Cornices

Likelihood

Possible-Likely

Expected Size

2 - 3

Cornices are large and fragile. Cornice falls could trigger avalanches on the slopes below. 

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine.

Valid until: Apr 21st, 2021 4:00PM

Forecast Trend

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