Archived

Avalanche Forecast

Mar 15th, 2015–Mar 16th, 2015

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

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Coast.

Newly formed winds slabs will present a high hazard for some time. Careful route selection is critical at this time

Confidence

Fair - Due to the number and quality of field observations

Weather Forecast

A Pacific frontal system will pass through the extreme southern portion of BC today ( Sunday) and into early Monday leaving us with 10 to 20cm of snow at higher elevations and rain below1200m. Moderate to strong winds above 1500m will accompany this system. Tuesday should see some clearing skies and very light precipitation late in the day, then more clearing for Wednesday.

Avalanche Summary

1 size 2 storm slab observed on a NW aspect in steep alpine terrain. Limited observations from yesterday due to low ceilings and poor visibility.

Snowpack Summary

10 to 20cm of recent storm snow now lies on a variety of crusts and old wind slabs above treeline. A crust that was beginning to break down and facet was buried around March 5 and may be the one to look for in the snowpack. Much of the new snow will have been redistributed by strong winds during parts of the storm. Below treeline the snowpack has had numerous warming and rain events and should be bombproof for the most part. Rain has recently been reported to ridge tops in the Coquihalla region. Solar aspects have been reported as isothermal in some areas below 1600m.

Avalanche Problems

Wind Slabs

Recent storm snow with strong winds will have built wind-slabs on lee slopes

The new snow will require several days to settle and stabilize.>Assess start zones carefully and use safe travel techniques.>Be aware of the potential for wide propagations due to the presence of hard windslabs.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 4

Cornices

New storm snow with strong winds will have added more mass to already ripe cornices. Warm spring-like temperatures may encourage cornice failures.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Stay well back from cornices.>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.

Likelihood: Unlikely - Possible

Expected Size: 1 - 4