Avalanche Forecast

Issued: Apr 14th, 2019 3:30PM

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

ghelgeson, Avalanche Canada

Lizard-Flathead.

Winter is going out with a bang after producing 30 cm of storm snow Saturday night. Rising temperatures and the strong April sun are expected to produce natural avalanche activity over the next few days.

Summary

Confidence

Moderate -

Weather Forecast

Well, we got "Fernied" Saturday night! This week ushers in a rather slack pattern for the Lizard Range with the big story being the steadily rising freezing level. It doesn't look like we'll get any significant precipitation this week. Enjoy the new snow before it really starts to warm up!SUNDAY NIGHT: Freezing level around 1000 m, moderate west/southwest wind, 1 to 5 cm of snow possible. MONDAY: Scattered cloud cover, freezing level rising to around 1500 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 2100 m, light variable wind, no significant snowfall expected. WEDNESDAY: Scattered cloud cover, freezing level rising to around 2200 m, moderate to strong west wind, no significant snowfall expected.

Avalanche Summary

A natural avalanche cycle occurred Saturday night, the highlights were storm slabs up to size 2 on northeast facing alpine terrain around 1700 m. A natural cornice failure was observed from a north facing ridgeline which subsequently triggered a size 2.5 storm slab involving the new snow. Control work produced storm slabs to size 2.We received a great MIN report of a small storm slab from Saturday morning, and this was well before the storm really kicked into gear. On Friday small loose wet natural avalanches were reported from steep south facing terrain.

Snowpack Summary

The Fernie Factor really kicked in late Saturday into early Sunday. The region picked up about 30 cm of snow (and 53 mm of water). This snow sits above a widespread supportive crust. Steep, north facing, alpine terrain may still hold a cold, dry, snowpack where fresh storm slabs are thought to be widespread. Steep north facing terrain is also harboring a deeply buried layer of facets. 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. It looks like it is going to warm up this week and all the new snow will likely produce a widespread and powerful loose wet cycle. During the heat of the day, especially under direct sun, the snow surface will become moist or wet almost everywhere (except for high elevation north) and loose wet avalanches could run far.Below treeline the snowpack has melted or is isothermal.

Problems

Storm Slabs

About 30 cm of storm snow rests on a widespread crust. The "crust free" exception may be high elevation north facing alpine terrain. Storm slabs likely remain sensitive to human triggering, especially in wind loaded terrain.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Sunny breaks combined with fresh storm snow will likely turbo charge 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.

A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.Loose avalanches may start small but they can grow large and destructive in these conditions.Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Valid until: Apr 15th, 2019 2:00PM