Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Feb 18th, 2015–Feb 19th, 2015

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

Regions

South Columbia.

The snow is best up high, but this is also where lingering avalanche concerns exist. Please become a member of Avalanche Canada today at avalanche.ca/membership.

Confidence

Good

Weather Forecast

The ridge of high pressure flattens on Thursday allowing a couple weak disturbances to cross the province. We should see more cloud with possible light flurries each day. The freezing level is around 1500-1700 m on Thursday and should lower to around 1000-1200 m by Saturday. Winds are light gusting moderate from the W-NW. The ridge rebuilds on Friday but we might not see full clearing until late Saturday. After this it looks like at least a few more days of dry and sunny weather.  

Avalanche Summary

For the past few days we have seen a few size 2-3 natural and explosive triggered slabs and cornice failures (sometimes triggering slabs and sometimes not) each day. Almost all of these have been from steep alpine terrain on a variety of aspects. On Tuesday there were also a few reports of loose wet slides from very steep south-facing slopes in the alpine.

Snowpack Summary

The snow surface is a mix of surface hoar, crusts, low density snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. At alpine elevations, new wind slabs may have formed from NW winds, and cornices are large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) continue to give variable results in snowpack tests. Chances of triggering these weaknesses have decreased, but triggering may be possible from thin or rocky snowpack areas; or perhaps with a cornice fall, or an avalanche stepping down, especially on sun drenched slopes.

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.