Lizard Range and Flathead Avalanche Forecast

Issued: Apr 16th, 2021 3:00PM

Sat Apr 17th Current Conditions
Alpine Considerable Treeline Considerable Below Treeline Considerable
Sun Apr 18th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate
Mon Apr 19th 3 Day Outlook
Alpine Moderate Treeline Low Below Treeline Low

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

 

As freezing levels rise, the likelihood for large cornice failures and wet loose avalanches will increase. Start early and plan to be off large slopes before the heat of the day.

Check out the latest Forecaster's Blog for more information on managing current conditions.

Summary

Confidence

Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.

Weather Forecast

FRIDAY NIGHT: Clear / light, northeast wind / alpine low +3 / Freezing level 2600 m. 

SATURDAY: Sunny / light southwest wind switching to northwest late afternoon / alpine high temperature +11 / Freezing level 2800 m.

SUNDAY: Cloudy with isolated showers or flurries; 3-9 cm / moderate northeast wind / alpine high temperature +3 / Freezing level dropping to 1400 m through out the day.

MONDAY: Mostly cloudy / light northerly winds / alpine high +3 / freezing level 1800 m.

Avalanche Summary

Naturally triggered wet loose avalanches from size 1-2.5 were reported in the last couple of days.

As freezing levels continue to rise and remain elevated overnight, the likelihood for large cornice failures and wet loose avalanches will increase. Cornice failures could trigger deeply buried weak layers on steep, rocky slopes with a shallow or thin to thick snowpack.

Snowpack Summary

Lingering wind slabs may still be reactive in isolated locations on steep northerly aspects in the alpine that still have dry snow. All other terrain has been undergoing a melt-freeze cycle with successive days of warm sunny weather. Things will be "more melt, less freeze" on Saturday as we do not expect a good overnight recovery. 

Strong solar radiation and warming will trigger more wet loose avalanches on Saturday as the snow loses cohesion. Cornices are large and fragile. Cornice falls could trigger avalanches on the slopes below.

The snowpack is overall strong and settled, although intense warming could potentially weaken deeper layers in steep, rocky terrain with a shallow or thin to thick snowpack. 

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

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

  • Extra caution is needed around cornices under the current conditions.
  • Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

Problems

Cornices

An icon showing Cornices

Likelihood

Likely

Expected Size

2 - 3

Strong solar radiation and warming may trigger the large cornices that hang over ridge lines. Cornice falls are a hazard on their own, but could also trigger avalanches on the slopes below.

Aspects:

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

Elevations:

Alpine.

Loose Wet

An icon showing Loose Wet

Likelihood

Likely-Very Likely

Expected Size

1 - 2.5

With potential for no overnight refreeze, expect natural and human triggered wet loose avalanches on a variety of aspects and elevations. Danger will be greatest on steep sun exposed slopes.

The more the snowpack warms-up and weakens, the more conservative you'll want to be with your terrain selection. Wet loose avalanches can entrain a lot of snow and cross elevation bands..

Aspects:

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

Elevations:

All elevations.

Valid until: Apr 17th, 2021 4:00PM

Forecast Trend

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