Avalanche Forecast

Issued: Mar 7th, 2013 9:16AM

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

jlammers, Avalanche Canada

South Coast.

Avalanche danger below treeline is LOW in the Cascades where the surface rain crust extends up to higher elevations.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

Friday: Mix of sun and cloud / Light northwest winds / Freezing level at 1600mSaturday: Clear skies / Light northwest winds / Freezing level at 1700mSunday: Light snowfall / Moderate southwest winds / Freezing level at 1200m

Avalanche Summary

There were no reports of new avalanches on Monday, Tuesday or Wednesday. Sun forecast for Friday and Saturday could trigger loose wet avalanche activity on steep solar features. Warming also has the potential to trigger deeper persistent slab avalanches.

Snowpack Summary

Light amounts of recent snow overlie 60-100cm of settling storm snow or a rain crust below 1400m in the north and 1700m in the south. These accumulations may exist as wind slabs in exposed areas.A weak layer of buried surface hoar (February 20th) and/or a crust sits at the base of the storm snow. This layer was the culprit in most of the large avalanches that occurred last weekend. Snowpack tests continue to show sudden planar results and good potential for propagation. Triggering this layer is becoming more difficult, but I recommend avoiding any large slopes that did not release during the last cycle, especially when the sun pokes out this week.

Problems

Persistent Slabs

60-120 cm of settling storm snow sits on a persistent weak layer of surface hoar. Extra caution should be given on all slopes over 30 degrees that did not previously slide, especially if the sun comes out.

Conditions have improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 7

Loose Wet

With forecast sun, loose wet avalanches will become likely on steep, sun-exposed slopes.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Wind Slabs

Although wind slabs have gained strength, they may still be reactive in steep, unsupported terrain.

Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Mar 8th, 2013 2:00PM