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Avalanche Forecast

Archived

Dec 7th, 2013–Dec 8th, 2013

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, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.

Regions

South Rockies.

Confidence

Poor - Due to the number of field observations

Weather Forecast

A weak disturbance may bring clouds and some flurries overnight into Sunday. The dominating arctic air mass will remain bringing very cold temperatures through the forecast period.Sunday: Cloudy in the morning with some snow accumulations up to 5 cm. Alpine temperatures are showing a high of -21. Light ridgetop winds from the North.Monday: Cloudy with some flurries near 4 cm. Alpine temperatures are showing a high of -20. Ridgetop winds strong from the SW. Tuesday: Cloudy with some sunny periods. Alpine temperatures are showing a balmy -14. Ridgetop winds are light from the West.

Avalanche Summary

No reports of avalanche activity.

Snowpack Summary

The South Rockies Field Team are back at it, Yeah! Snowpack depths at treeline seem to vary from 80 - 120 cm. Earlier this week the region received storm snow amounts of up to 70 cm. Strong ridgetop winds from the N-NE has redistributed snow onto S-SW aspects, creating reverse loaded slopes. Widespread wind effect is noticeable in the alpine and at treeline, but reports suggest they are stubborn to trigger.Below the recent storm snow down 30-40 cm a surface hoar/ facet/ crust interface. Snowpack testing showed easy results and some whumphing (failure of a weak layer below your feet). If you're seeing or feeling this, consider it a direct indicator of a buried weakness below.Near the base of the snowpack, I suspect you will find sugary facets, which will surely be growing with the extremely cold temperatures. The chance of triggering this layer is quite small under the current conditions, but if it was to happen, it would most likely be on a steep, convex slope with a thin snowpack.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

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.