Avalanche Forecast Lizard Range and Flathead

Date Issued: Valid Until:

Avalanche Canada ghelgeson, Avalanche Canada

Avalanche Forecast

Sat Apr. 13th ยท 4:26PM

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
Storm Slabs Storm Slabs
Loose Wet Loose Wet

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Low

Below Treeline

Danger Ratings Low

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Low

Below Treeline

Danger Ratings Low
If we wake up to more than 20 cm of storm snow, then these danger ratings should all be bumped up one level, so moderate becomes considerable. New snow and wind Saturday night may produce a natural avalanche cycle if the "Fernie Factor" kicks in...

Confidence

Low - Timing, track, or intensity of incoming weather system is uncertain on Saturday

Weather Forecast

A frontal system should track into the region late Saturday into Saturday night. We're expecting it to be quite convective which makes it hard to pin down total snow amounts, but right now it sounds like the storm could produce up to 10 cm before dark, and another 8 to 15 cm Saturday night, possibly more if the notorious Fernie Factor kicks in.SATURDAY NIGHT: Freezing level around 1500 m, moderate to strong southwest wind, 8 to 15 cm of snow.SUNDAY: Scattered cloud cover initially building to broken cloud cover in the afternoon, freezing level around 1600 m, moderate to strong west/southwest wind, 4 to 8 cm of snow possible. MONDAY: Scattered cloud cover, freezing level rising to around 1700 m, light variable wind, trace of snow possible. TUESDAY: Scattered cloud cover clearing to just a few clouds around lunch, freezing level rising to around 2000 m, light variable wind, no significant snowfall expected.

Avalanche Summary

On Friday small loose wet natural avalanches were reported from steep south facing terrain.On Thursday, explosive control was able to initiate a few loose dry avalanches up to size 1.5 which failed in the recent storm snow. In the afternoon skier controlled loose wet avalanches were easily triggered at treeline and below up to size 1.5 on sunny aspects. No natural avalanche activity was reported and no new avalanches were noted in alpine elevations.

Snowpack Summary

15 cm Thursday night brings 20-35 cm of recent accumulated snow since last weekend which sits above a supportive crust at treeline and in the alpine. During the heat of the day, especially under direct sun, the snow surface becomes moist or wet almost everywhere. The exception being high elevation north facing features. Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where isolated reactive wind slabs may exist and a well settled slab rests on weak facets (sugary snow). Although unlikely, human triggering of persistent slabs on this layer may still be possible, especially in rocky alpine terrain with a shallow or highly variable depth snowpack. Below treeline the snowpack is becoming isothermal.

Problems

Storm Slabs

Storm Slabs

Watch for fresh slab development, especially in high elevation north facing features where human triggering is most likely near ridgecrest. High elevation south and west slopes could produce heavy sluffing as the new snow slides on a crust.

Recent new snow may be hiding windslabs that were easily visible before the snow fell.Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Possible

Expected Size

1 - 2

Loose Wet

Loose Wet

Sunny periods Sunday combined with fresh storm snow will likely initiate loose wet avalanche activity. The likelihood of loose avalanches increases as temperatures warm throughout the day and/or if the sun comes out for an extended period of time.

Loose avalanches may start small but they can grow and push you into dangerous terrain traps.A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.Brief periods of sun could quickly initiate natural avalanche activity.

Aspects: South East, South, South West, West.

Elevations: Alpine, Treeline.

Likelihood

Likely - Possible

Expected Size

1 - 2