Archived

Avalanche Forecast

Feb 18th, 2012–Feb 19th, 2012

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

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: Purcells.

Confidence

Good

Weather Forecast

We're entering a more active pattern which should persist through the middle of next week.Sun: A ridge of high pressure rebuilds during the day allowing temperatures to cool slightly while winds ease and switch from the SW to NW. A bit of instability from Saturday's storm will produce the odd flurry, but skies should clear in the afternoon. Look for 1500m temps to climb to -2 during the day.Mon/Tue: A few weak systems pass over the region favoring west slopes. Nothing in the flow is particularly well organized, it's the kind of setup that has the potential to bring 2-4 cm a day. Precip totals will be quite variable throughout the region, favoring the west slopes. 1500 m temps: High -3, Low -7

Avalanche Summary

No new avalanche activity reported Thursday or Friday.

Snowpack Summary

Widespread surface hoar has been buried by 5 - 10 cm of new snow in most of the region. The exception is terrain closer to the bugs where the interface is down 20-40cm. A melt-freeze crust has developed on southerly aspects at all elevations. North and east aspects continue to have dry snow and some surface sloughing in steep terrain. Basal facets have not been reactive, but operators continue to monitor this layer in tests. Triggering this deep persistent weak layer is unlikely, but shallow snowpack areas or shallow weak areas adjacent to deeper wind loaded slopes are suspect locations.

Avalanche Problems

Wind Slabs

Fri/Sat winds were out of the S, SW. Winds should switch to the NW Sun. This combination has made for thin windslabs in wind exposed terrain features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3

Deep Persistent Slabs

Although a deep persistent slab would most likely require a large trigger (such as cornice fall), they are still possible; especially in thin snowpack areas or in unsupported, rocky terrain.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Unlikely

Expected Size: 3 - 7