Archived

Avalanche Forecast

Mar 17th, 2013–Mar 18th, 2013

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Regions: Cariboos.

Confidence

Fair - Due to limited field observations on Saturday

Weather Forecast

Monday: Light snowfall / Moderate to strong northwest winds / Freezing level at 1100mTuesday: Mix of sun and clouds / Light southwest winds / Freezing level at 1000mWednesday: Moderate snowfall / Moderate southwest winds / Freezing level at 1300m

Avalanche Summary

A widespread avalanche cycle to size 3 took place prior to the weekend. Observations were very limited on Saturday; however, with new snow and wind I would expect a new round of wind slab activity on Sunday. There is also ongoing potential to trigger deeper storm slabs.

Snowpack Summary

Generally moderate amounts of new snow fell on Saturday night and have have been distributed into deeper windslabs in lee terrain. These new accumulations overlie a deep and cohesive storm slab which formed last week with strong winds, very heavy snowfall and warm temperatures. This deep storm slab produced widespread and destructive avalanches in the region and may take some time to fully stabilize as it overlies weak surface hoar buried on March 10th. At lower elevations heavy rain penetrated the snowpack; however, subsequent cooling has helped strengthen the snow.Deeper weaknesses in the snowpack have now become unlikely to trigger.Widespread cornice development has also taken place, and cornices are reported to be very large and weak.

Avalanche Problems

Storm Slabs

New snow accumulations have added load to an existing storm slab problem which produced destructive natural avalanches prior to the weekend. Current reactivity is most likely in areas where buried surface hoar exists.

Be wary of slopes that did not previously avalanche - even on low angle terrain.>Avoid exposure to overhead avalanche terrain, as large avalanches may reach the end of runout zones.>Conditions have improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1 - 6

Wind Slabs

New snow on Saturday night and continued very strong winds have created new wind slabs. Watch for loading on a variety of aspects due to variable wind directions.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Avoid travelling in areas that have been reverse loaded by northerly winds.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Cornices

Recent stormy weather has formed large and potentially weak cornices. Cornice falls may be highly destructive, and could also trigger large avalanches on the slope below.

Pay attention to overhead hazards like cornices.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood: Possible - Likely

Expected Size: 1 - 5