Avalanche Forecast

Archived

Feb 28th, 2022–Mar 1st, 2022

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Natural avalanches possible, human triggered probable.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Natural avalanches unlikely, human triggered possible.

Regions

Glacier.

The timing and track of the incoming storm is uncertain.

Anticipate danger ratings to rise Tuesday, likely culminating in avalanche control with explosives tomorrow afternoon.

Weather Forecast

Conflicting weather models are uncertain with snowfall amounts/winds, but agree that a warming trend is here until Thurs

Tonight: Cloudy, Alp low -5*C, gusty strong SW winds

Tues: Flurries, 10cm, Alp high -3*C, FZL 1800m, mod/ gusty extreme SW winds

Wed: Sun and cloud, isolated flurries, Alp high -5*C, FZL 1500m, light to mod gusty SW winds

Snowpack Summary

25-30cm of storm snow overlies a facet layer, small surface hoar in sheltered areas Treeline and below, and a sun crust on steep solar aspects. The Feb 15 surface hoar/sun crust is down 50-80cm and has not been reactive in tests the last few days, but may re-awaken with the new load and warming temps.

Avalanche Summary

Several natural avalanches were detected in the hwy corridor off Mts Tupper and Macdonald early Monday morning.

A skier triggered sz 2 in the Connaught Path Sunday shows the new snow is not yet bonded to the underlying bed surface.

A field team in the Fidelity area was able to ski-cut short rolls and "pop" out small 20-30cm storm slabs.

Confidence

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

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

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.

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.