Avalanche Forecast

Issued: Feb 10th, 2014 8:40AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs.

slemieux, Avalanche Canada

Kootenay Boundary.

If snowfall amounts are greater than 10-15 cm, consider the danger rating to be higher than posted. If this is the case, stick to low angle and low consequence terrain.

Summary

Confidence

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

Weather Forecast

Synopsis: A strong Westerly offshore flow pattern is becoming established which is allowing a series of systems to come through for the remainder of the week. Tonight and Tuesday: Snowfall should pick up tonight as the first system is passing through. 10-15 cm is expected overnight and light precipitation during the day tomorrow. Winds blowing strong from the SW and freezing levels staying at the surface.Wednesday: Locally heavy precipitation is forecasted with the second system, especially in the Southern part of the region. Amounts could reach 20-30 cm. Winds are forecasted to be strong from the SW. Freezing levels rising briefly to 1500 m. during the day. Thursday: Another disturbance is moving in but the timing is uncertain. Light amounts are expected with similar freezing levels and winds.

Avalanche Summary

There has been a report of a skier triggered slab avalanche size 1 on an E facing slope and of loose snow avalanches size 1 in steep terrain on all aspects. Expect more and bigger avalanches this week with the incoming weather.

Snowpack Summary

First pulse of precipitation has started adding load to the snowpack. With around 10-15 cm of new snow and strong SW winds on the underlying weak surfaces, natural avalanche activity will be possible especially on alpine and treeline slopes lee of winds. The new snow is sitting on a variety of weak layers such as surface facets, on a new surface hoar layer in sheltered areas, on a crust on solar aspects or on hard windslabs in the alpine. 20-50 cm below the surface, exist another surface hoar or suncrust layer that has been reactive to skier traffic even since it has been buried in late January. Anticipate that there is a good chance that avalanches will step down to this deeper buried weak layer, resulting in bigger than expected storm avalanches. The mid snowpack is strong and supportive. Deeper persistent layers have been dormant, however, they could wake up in the near future with the large load forecasted on Tuesday night.

Problems

Storm Slabs

Storm avalanches could step down to the late January weak layers. Windslabs lee on SW-W winds in the alpine and at treeline and widespread loose avalanches are also a concern.

Be aware of the potential for larger than expected storm avalanches due to the presence of buried surface hoar.>Choose conservative terrain and watch for clues of instability.>Avoid freshly wind loaded aspects.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Valid until: Feb 11th, 2014 2:00PM