Archived

Avalanche Forecast

Feb 15th, 2016–Feb 16th, 2016

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

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

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: Kootenay Boundary.

More snow and wind overnight will keep avalanche danger elevated on Tuesday. Be careful as you move into wind-affected terrain.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Tonight and Tuesday: 10-15 cm of snow overnight followed by cooling and clearing during the day. The freezing level peaks near 1600-1800 m overnight and lowers to 1400-1500 m during the day. Ridge winds are strong from the SW easing to moderate during the day. Wednesday: Showers or flurries with sunny breaks. The freezing level rises to 1800-2000 m. Winds are light and variable. Thursday: Periods of snow. The freezing level drops to 1200 m and winds increase to moderate or strong from the SW.

Avalanche Summary

Numerous size 1-2 explosive or skier controlled avalanches were reported throughout the region on Sunday. One size 2 accidentally triggered slab avalanche was reported in the Northern Rossland Range on Saturday. This avalanche was about 40 cm deep and was triggered on a NE aspect. One person was partially buried but escaped unharmed.

Snowpack Summary

30-50 cm of recent storm snow sits on a supportive crust at and below treeline, a breakable crust on south-facing slopes in the alpine, buried surface hoar in sheltered terrain, or old wind affected surfaces. Moderate south-southwest winds have created fresh dense wind slabs on exposed leeward slopes. A few buried surface hoar layers exist in the top 100 cm in drier areas on the west side of the region. In other areas the notable early January surface hoar layer is 80-130 cm deep and poses a low probability/ high consequence threat. It should remain on your radar, especially in thin snowpack areas and during periods of significant warming or rapid loading.

Avalanche Problems

Storm Slabs

Storm slabs continue to build. The recent storm snow sits on a melt-freeze crust or surface hoar and could be sensitive to human triggering, particularly in wind-loaded terrain.

The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Loose Wet

Expect loose wet sluffs on sun-exposed slopes if the sun is strong or if it's raining.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Persistent Slabs

Additional loading by new snow and wind, warming, and sunny periods could reactivate buried surface hoar. This is more likely in drier areas where surface hoar is found in the upper metre of the snowpack.

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

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 2 - 5