Avalanche Forecast

Issued: Apr 5th, 2016 8:32AM

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

pmarshall, Avalanche Canada

Purcells.

Danger could rise quickly if the sun makes an appearance in the afternoon. Keep an eye on the surface condition. If the snow is becoming moist or wet, plan on a more conservative approach.

Summary

Confidence

Moderate

Weather Forecast

WEDNESDAY: Cloudy with light snow to start (5 cm), and possible sunny breaks in the afternoon. The freezing starts around 1800 m and climbs to 2300-2400 m late in the day. Winds are moderate to strong from the West. THURSDAY: Mainly sunny. The freezing level shoots up to 3400 m. Winds should ease to light and variable. FRIDAY: Mainly sunny. The freezing level stays above 3000 m and winds should remain light.

Avalanche Summary

One size 2.5 slab avalanche was observed near Golden on Monday. This wet slab was accidentally triggered by skiers late on Sunday on a sun-exposed alpine slope. Cloud and slightly cooler temperatures put a hold on natural avalanche activity on Monday and Tuesday. However, this could be a brief respite before warmth and sunshine (and subsequent avalanche activity) return later in the week.

Snowpack Summary

A dusting of new snow sits on a fairly solid crust at all elevations and on all aspects. The exception to this could be high north-facing slopes where cold dry snow might still exist. Forecast snow and wind on Wednesday could combine to create fresh pockets of wind slab in lee alpine terrain. The March 22nd rain crust is 30-40 cm deep and is present to around 2000 m. The late February persistent weak layer is now down 40-100 cm below the surface. Both of these persistent weaknesses could wake up again as temperatures soar and the sun returns later this week.

Problems

Loose Wet

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices are large and weak and could pop off naturally as temperatures rise and the sunshine returns.

Do your best to avoid traveling on or underneath cornices. If you have to, move quickly and only expose one person at a time.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Persistent Slabs

The chance of slabs failing on buried persistent weaknesses will be on the rise this week. Extra caution is necessary if the snow becomes wet and slushy.

A few different buried persistent weak layers (PWL's) are lurking in our snowpack which means there is potential for large destructive avalanches that have the capability to run full path.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Apr 6th, 2016 2:00PM