Lizard Range and Flathead Avalanche Forecast

Issued: Mar 8th, 2020 5:00PM

Mon Mar 9th Current Conditions
Alpine Considerable Treeline Moderate Below Treeline Moderate
Tue Mar 10th 2 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate
Wed Mar 11th 3 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate

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

Storm slabs and loose avalanches were touchy Sunday and are expected to remain that way Monday as the storm snow feels the strong March sun for the first time. The new snow needs a bit of time to stabilize before we start gunning for the bigger objectives.

Summary

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

Enjoy the sun Monday.

SUNDAY NIGHT: Freezing level at valley bottom, light southwest wind, trace of snow possible.

MONDAY: Clear skies, freezing level rising to about 1300 m, light southwest wind, no significant precipitation expected.

TUESDAY: Clear skies in the morning becoming cloudy after lunch, freezing level rising to about 1600 m, moderate west/southwest wind, no significant precipitation expected during the day, potential for 5 to 10 cm of snow at upper elevation Tuesday night.

WEDNESDAY: Broken cloud cover, freezing level holding at 1500 m, light west/northwest wind, trace of snow possible.

Avalanche Summary

On Sunday loose dry and soft slab avalanches were sensitive to human triggering and control work to size 1.5. Avalanches have been 10 to 20 cm in depth, running fast and far. The storm snow is expected to remain sensitive to human triggering Monday.

Snowpack Summary

The Friday/Saturday storm produced 20 to 35 cm of new snow which buried heavily wind affected surfaces in exposed areas as well as a sun crust that is present to ridge top on solar aspects. Temperature crusts extend up to 1900 m on other aspects. This storm snow has not yet bonded to the old surfaces and is touchy.

A thick rain crust that has facets associated with it sits 30-60 cm below the surface and can be found up to ridgetops. We have only seen one avalanche on this layer since February 17th. The mid-pack is well settled and strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.

Terrain and Travel

  • The new snow could use a day or two to settle and stabilize before we start to tee up the bigger lines.
  • Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
  • As surface loses cohesion due to melting, loose wet avalanches become common in steeper terrain.
  • Extra caution is needed around cornices under the current conditions.

Problems

Storm Slabs

An icon showing Storm Slabs

Likelihood

Likely

Expected Size

1 - 2

20 to 35 cm of new snow has settled into storm slabs that have been running fast and far. Warming temperatures and clear skies Monday should allow the new snow to remain sensitive to human triggering.

Aspects:

All aspects.

Elevations:

All elevations.

Cornices

An icon showing Cornices

Likelihood

Possible-Likely

Expected Size

1 - 2

Cornices have grown large and loom over many ridge lines. They have potential to fail naturally as well as under the weight of a person or machine and they may trigger slabs on slopes below them. Give them a wide berth.  

Aspects:

North, North East, East, South East.

Elevations:

Alpine.

Loose Wet

An icon showing Loose Wet

Likelihood

Possible-Likely

Expected Size

1 - 1.5

Beware of wet loose avalanches releasing naturally on steep slopes exposed to the sun.

Aspects:

South, South West, West.

Elevations:

Alpine, Treeline.

Valid until: Mar 9th, 2020 5:00PM