Lizard Range and Flathead Avalanche Forecast

Issued: Apr 18th, 2021 4:00PM

Mon Apr 19th Current Conditions
Alpine Moderate Treeline Low Below Treeline Low
Tue Apr 20th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate
Wed Apr 21st 3 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate

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

Watch for wind slabs in drifted areas at upper elevations, especially near ridge-crests, roll-overs, and in steep terrain. 

Summary

Confidence

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

Weather Forecast

Sunday night: Decreasing cloud, isolated flurries with trace accumulations, moderate northeast winds, alpine temperature -10 C, freezing level dropping to valley bottom.

Monday: Mix of sun and cloud, light northeast winds, alpine high temperature -3 C, freezing level 1700 m.

Tuesday: Sunny, light variable winds, alpine high temperature -2 C, freezing level 2300 m. 

Wednesday: Sunny, light southwest winds, alpine high temperature -3 C, freezing level 2500 m. 

Avalanche Summary

Natural wet loose avalanches, ranging from size 1-2.5, were reported over the past few days.

Snowpack Summary

An upslope storm brought 5-10 cm of new snow to the region, with up to 15 cm accumulating in favored areas. Moderate northeast winds with strong ridgetop gusts have formed fresh wind slabs in exposed areas at upper elevations. Cornices are large and fragile. Cornice falls could trigger avalanches on the slopes below.

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

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Stay off recently wind loaded slopes until they have had a chance to stabilize.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Extra caution is needed around cornices under the current conditions.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

New snow totals varied across the region, with anywhere from a trace to 15 cm of accumulation. Where higher accumulations of new snow have combined with moderate northeast winds, there are likely reactive wind slabs in lee terrain features. 

Aspects:

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

Elevations:

Alpine, Treeline.

Valid until: Apr 19th, 2021 4:00PM

Forecast Trend

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