Avalanche Forecast

Issued: Mar 8th, 2013 8:44AM

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

triley, Avalanche Canada

South Columbia.

Periods of strong solar radiation may cause a cycle of natural avalanche activity in the new snow. Avalanches in motion or cornice fall may trigger deep slab instabilities.

Summary

Confidence

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

Weather Forecast

Overnight and Saturday: Mostly sunny with light to moderate Northwest winds and freezing level rising to about 1400 metres. The ridge of high pressure is expected to flatten out Saturday evening allowing cloud and light precipitation to move into the region by Sunday morning.Sunday: Expect 10-15 cms of new snow starting in the morning, combined with moderate Southwest winds. Freezing level should be about 1400 metres.Monday: Unsettled weather is forecast for Monday with cloudy skies and light West winds. Models are not in agreement for Monday. Hopefully we will know more tomorrow.

Avalanche Summary

Some small loose dry avalanche were reported from steep terrain on northerly aspects in the alpine. A thin layer of new snow was becoming moist and sliding easily on a recent layer of sun crust on Southerly aspects in the alpine and at treeline. There was one report that was 24 hours old of a remotely triggered avalanche that released down to the February 12th weak layer of buried surface hoar.

Snowpack Summary

There is a thin layer of new snow and wind transported new snow above various sun crusts and old storm slabs, that may release naturally or be easily triggered during periods of strong solar radiation on Southerly aspects. The storm slab continues to settle, and is becoming more stubborn to trigger. The weak layer of surface hoar that was buried on February 12th is now down about 100-150 cms and continues to be triggered by light additional loads on Southerly aspects where it is sitting on an old sun crust. Larger loads like cornice fall or explosives have been able to trigger this layer on various aspects in the alpine and at treeline. If we get a period of strong solar radiation, then we may see another cycle of natural activity on Southerly aspects resulting in large destructive avalanches.

Problems

Persistent Slabs

There is a weak layer of buried surface hoar down about 100-150 cms that may be triggered by large loads like re-grouping, cornice fall, or smaller avalanches in motion. Strong solar radiation may initiate this layer where it sits on a crust.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

4 - 7

Storm Slabs

The storm snow is settling and bonding, but may continue to be triggered by human activity. Periods of strong solar radiation may cause a cycle of storm snow releases on Southerly aspects.

The recent storm slab will require several days to settle and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Loose Wet

The new snow may release naturally or be easily triggered during periods of strong solar radiation. Avalanches in motion may step down to deeply buried weak layers resulting in large avalanches.

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: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Mar 9th, 2013 2:00PM