Lizard Range and Flathead Avalanche Forecast

Mar 23rd, 2020 4:00PM

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

There is uncertainty in the forecast due to a lack of data available at this time.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain. Uncertainty is due to the limited number of field observations.

Weather Forecast

MONDAY NIGHT: Cloudy with flurries, accumulation 2 to 5 cm, moderate to strong southwest wind, alpine temperature -8 C.

TUESDAY: Cloudy with flurries, accumulation 5 to 10 cm, moderate southwest wind, alpine temperature -8 C, freezing level 1100 m.

WEDNESDAY: Cloudy with flurries, accumulation 5 to 10 cm, light southwest wind, alpine temperature -7 C, freezing level 1100 m.

THURSDAY: Clear skies, light southwest wind, alpine temperature -6 C, freezing level 1500 m.

Avalanche Summary

No new avalanches were observed from limited reports on Monday. Looking forward, wind slab activity may increase as new snowfall and wind forms fresh slabs.

Snowpack Summary

Snowfall and southwest wind are forecast for the coming days, which will form wind slabs in exposed terrain. Expect the slabs to be thickest and most reactive in lee terrain features adjacent to ridge lines. The slabs will sit on a melt-freeze crust on sun-exposed slopes or previously wind-affected snow, so these slabs may take some time to bond to the snowpack.

A layer of faceted grains overly a melt-freeze crust from early February. This layer currently sits 30 to 60 cm below the surface. This layer remains dormant and has not produced a reported avalanche for about a week.

The base of the snowpack may contain a weak layer of faceted grains that are most prominent in shallow rocky start zones with a snowpack depth of 150 cm or less.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Make conservative terrain choices and avoid overhead hazard.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

Wind slabs will form as new snow falls with strong southwest wind. Apply added caution in exposed terrain, particularly in lee slopes near ridges.

Aspects:

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

Elevations:

Alpine, Treeline.

Valid until: Mar 24th, 2020 5:00PM