Avalanche Forecast

Issued: Mar 19th, 2015 3:00PM

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

Alberta Parks matt.mueller, Alberta Parks

Forecasters feel that we will be near the upper limit of moderate in the alpine for Friday. Use small terrain to test the snow and get an idea of how the bigger features will behave.

Summary

Confidence

Good

Weather Forecast

Freezing levels will drop to 1900m tonight with winds continuing to blow out of the west, gusting to 75km/hr. No snow is expected overnight. Another cloudy day is on deck for tomorrow. Some flurries will roll through, but accumulation will be limited. Up to 4cm's is expected.  The alpine temperatures will rise to near zero by mid afternoon. Winds will settle down to moderate values with occasional gusts of 50km/hr. The freezing level will rise to 2200m once again. A mild system is expected to pass through our area over the week-end. Precip amounts have been dropping with each update, but we may still get a refresh tomorrow night.

Avalanche Summary

No new observations from today. There were numerous loose wet avalanches from yesterday's heat. All aspects/elevations had loose wet issues. The largest would have been sz2.

Snowpack Summary

Overnight lows have been high enough lately to prevent a solid freeze below treeline. By early afternoon the valley bottom snowpack is near isothermal and higher elevations are seeing moist snow on solar aspects. At treeline the surface varies from sun/temperature crust on solar aspects to fresh windslabs on lee features. The recent snow has been blown into the low areas where there is a crust underneath. No avalanches have occurred on this interface yet, but its likely there are isolated pockets of touchy windslab in crossloaded features. The alpine is a mix of windslab and wind disturbed, but still soft snow. Winds were variable today so expect to see windslabs of varying density on all aspects.

Problems

Wind Slabs

An icon showing Wind Slabs
These new slabs are currently in open treeline areas and immediate lee features in the alpine. On solar aspects, the underlying interface is likely a crust. Expect them to be more touchy in those areas.
Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Spot probing today revealed the weak basal layers. Steep shallow areas remain a concern for triggering.
Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Mar 20th, 2015 2:00PM

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