Avalanche Forecast

Issued: Mar 21st, 2016 9:19AM

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

Avalanche Canada bcorrigan, Avalanche Canada

Cornices and solar aspects are important to watch right now. Pay close attention to rising temperatures.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

A series of Pacific frontal systems will pass through the area in the next 4 days bringing cloudy skies and small amounts of precipitation. TONIGHT: Snow flurries above 1800m, light rain below. 12 TUESDAY: Cloudy with flurries and/or light rain, no significant precipitation. The freezing level will drop to 1200 m overnight, then climb to 1800m during the day, winds will be light, south to south west. WEDNESDAY: Light precipitation in the late afternoon, winds forecast to be light from the south, freezing level dipping overnight to 1000 m, then climbing to 1600 m during the day. THURSDAY: 10mm of precipitation in the forecast with the freezing level at 1400m early in the day and rising to 1600 in the afternoon. 10 to 15 cm of snow accumulation possible above1200m, winds are forecast to belight from the west.

Avalanche Summary

There are several reports from yesterday of loose-wet and moist point release avalanches, some natural and some skier triggered. Snowballing and pinwheeling have also been mentioned in the region on steep southerly aspects. No reports of cornice failures from yesterday, but they are still on everyone's mind!

Snowpack Summary

Warm temperatures and strong solar radiation have encouraged bonding of the last blast of storm snow. Be aware that there are still multiple buried crusts at treeline and below, but they have not been reactive recently. The late February (Feb 27th) persistent weak layer of buried surface hoar, is now down 70 to 120 cm. This layer has been the interface for some large avalanches and is worth keeping in mind ( and perhaps looking for by digging a test pit) We suspect that this weak layer is more prominent on northerly (shaded) aspects at and above 1700 m. It may also be found associated with a crust on solar aspects. There have not been avalanches on this layer recently, but it is still a concern in the region. The potential is there for deep weak layers to become reactive. Cornices and exposure to cornice run-outs are definitely still something to be concerned about. Light to moderate south winds accompanying the incoming precipitation may build wind slabs on lee ( N-NW ) features in the coming days. As the sky clouds over and the freezing level lowers, it's worth paying attention to moist or wet surface snow.

Problems

Storm Slabs

An icon showing Storm Slabs
The storm slab has settled well and is not expected to be a problem soon.  It might still be triggered in high north facing terrain.
Choose well supported conservative lines and watch for clues that indicate instability.>Avoid freshly wind loaded features.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
This weak layer might again become reactive with additional loading.  A cornice failure might provide the load needed to trigger it.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar. >Surface avalanches in motion could step down and initiate persistent slab avalanches which have the potential to be large and destructive.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 5

Loose Wet

An icon showing Loose Wet
A loose-wet  surface avalanche might trigger deeply buried instabilities and produce a large destructive avalanche
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East, South East.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 22nd, 2016 2:00PM

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