Avalanche Forecast

Issued: Mar 17th, 2014 11:15AM

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

jlammers, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Tuesday

Weather Forecast

Overview: A ridge of high pressure will bring dry conditions to the region on Tuesday. A frontal system will bring moderate snowfall on Wednesday before the dry ridge rebuilds on Thursday.Tuesday: Generally clear skies / Light to moderate northwest winds / Freezing level at 1500mWednesday: 15-25cm of snow / Moderate to strong southwest winds / Freezing level at 1400mThursday: Mix of sun and cloud with light flurries / Moderate northwest winds / Freezing level at 700m

Avalanche Summary

Although observations were extremely limited, several natural size 1-1.5 loose wet avalanches were observed on Sunday. They occurred in response to steady rain at lower elevations. Looking forward, solar radiation may be the driver for natural avalanche activity on Tuesday.

Snowpack Summary

Variable amounts of recent storm snow was blown by strong winds into much deeper deposits in lee terrain. These recent accumulations overlie crusts on previously sun-exposed slopes and surface hoar in shaded terrain. Rain at lower elevations continued to saturate the snowpack. If the air temperature dips below freezing, lower elevation surfaces may exist as a refrozen crust.Below the new snow, 60-100cm of settled snow has been bonding poorly to buried surface hoar and crusts. The deeper facet/crust persistent weakness buried at the beginning of February, now down 60 to 160cm, has been highly variable in terms of reactivity and is still very difficult to trust. Needless to say, any avalanche at these deeper, persistent interfaces would be large and destructive.Weak basal facets exist in many areas, but without a large load, triggering now is unlikely.

Problems

Deep Persistent Slabs

Deep persistent weaknesses buried at the beginning of February are still a concern amongst professionals in the region. Large cornices failing due to solar radiation are a possible trigger. Any persistent avalanche would be large and destructive.

Be aware of the potential for large, deep avalanches due to the presence of buried weak layers.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Storm Slabs

Recent storm accumulations overlie a number of potentially weak surfaces. Watch for increased triggering in wind exposed terrain or when solar radiation is strong.

Be cautious as you transition into wind affected terrain.>Be alert to conditions that change with elevation.>Make observations and assess conditions continually as you travel.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Loose Wet

If the sun comes out on Tuesday, pushy loose wet avalanches may fail with the potential to trigger deeper slabs..

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be alert to conditions that change with elevation.>

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 18th, 2014 2:00PM