Avalanche Forecast

Archived

Jan 28th, 2015–Jan 29th, 2015

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Natural avalanches unlikely.

Regions

Glacier.

If the solar is strong today it may result in some avalanche activity or cause cornices to fail which may trigger deeper instabilities. Expect challenging ski conditions.

Weather Forecast

Wednesday and Thursday expect low cloud and sun in the alpine. Temps have cooled off with a high of -5'C, light to moderate SW winds and no snow. On Friday, a frontal system will bring light flurries but only a trace of snow.

Snowpack Summary

Light dusting overnight on breakable crust over moist snow to ~2400m. Above 2400m snow is heavily wind affected. The Jan15 surface hoar layer is down 60-90cm is becoming more stubborn to trigger but is still likely to propagate. The Dec 17 surface hoar/ crust complex is down 130-180cm and is still reactive in snowpack tests. Cornices grew large.

Avalanche Summary

Natural avalanche activity has tapered off with cooling. Recent avalanche control triggered slab avalanches to size 3 failing on the Jan 15th layer.

Confidence

Problems

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.