Archived

Avalanche Forecast

Mar 21st, 2015–Mar 22nd, 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

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

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

Regions: Kootenay Boundary.

Loose wet avalanches can really pack a punch at this time, especially below treeline as the temperature rises above freezing.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Monday

Weather Forecast

Sunday: Clear skies in the morning, cloud cover increasing throughout the day. Light S winds at treeline, moderate SW at ridgetop. No significant precipitation expected. Freezing level rising to 2000m.Monday: Overcast all day. 1 to 6mm of precipitation, 1 to as much as 15cm of convective snowfall. Freezing level at 1700m. Light NW winds at all elevations. Tuesday: Overcast skies. Freezing level at 1500m. Light variable winds at all elevations. No significant precipitation expected.

Avalanche Summary

Numerous natural and rider triggered avalanches to size 2 were reported Friday as moist storm snow slid on the robust mid-March crust.

Snowpack Summary

15 to 30 cm of new snow rests on the 15cm thick mid-March crust. Wind loaded features may have as much as 60 cm on the crust. During the heat of the afternoon, the snow surface has been reported to be moist or wet at all elevations on solar aspects and up to 2000m on north aspects. At many elevations, melt-freeze cycles are occurring with a weak surface crust forming overnight and then breaking down during the afternoon. Up to 35cm of snow from last weekends storm sits over the mid-March rain crust. Reports suggest that this snow is bonding well to the crust. Older deeply buried persistent weak layers still exist in the snowpack but are no longer expected to be reactive.

Avalanche Problems

Wind Slabs

Watch for wind slabs at and above treeline, especially near ridge crest and lee of mid slope features like rock outcroppings and ribs.

Use ridges or ribs to avoid pockets of wind loaded snow.>Avoid freshly wind loaded features.>Be careful with wind loaded pockets, especially near ridge crests and roll-overs.>

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 3

Loose Wet

Small amounts of new snow resting on a crust combined with above freezing temps below 2000m are contributing to an active loose wet problem. These avalanches could quickly entrain mass growing bigger and running further than expected.

Watch for clues, like sluffing off of cliffs, that the snowpack is warming up. >Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3