Avalanche Forecast

Archived

Dec 25th, 2016–Dec 26th, 2016

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely.

Regions

Little Yoho.

Light temperature inversion in the valley is making the alpine very pleasant. Enjoy the clear weather. Happy Holidays!

Weather Forecast

Clear sky's will prevail till tomorrow afternoon when a small system is expected to push in, this will bring light precipe with accumulations up to 15 cm.

Snowpack Summary

10-40 cm sits over the very weak Dec.19th facets. Wind slabs up to 60cm have been observed over this same layer in alpine areas. The new snow / facet interface has proven touchy with avalanche control work over the last 5 days and will persist for some time. The Nov crust is 30-80cm deep and a few isolated observations indicate it to be reactive.

Avalanche Summary

Explosive control this week resulted in avalanches up to size 2.5-3. The largest involved windslabs that failed on the persistent Dec.19th facets. Notably, ski hills triggered a couple of size 2's with bombs that initiated on the Nov 12 crust on solar aspects where both a thin snowpack and pronounced crust exist. Limited natural activity seen

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.

Loose Dry

Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.