Avalanche Forecast

Issued: Apr 3rd, 2014 9:19AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.

Avalanche Canada bcorrigan, Avalanche Canada

Snowfall amounts and solar input are driving the hazard ratings at this time. More snow or more sun than anticipated may push the hazard higher than forecast.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Synopsis: A  slow moving frontal system will bring precipitation into the BC interior.Tonight: Cloudy with flurries, some parts of the region may receive 15 to 25cm of precipitation. No overnight freeze, freezing levels up to 1300m, Winds moderate, gusting to strong from the south west.Friday: Cloudy with flurries, parts of the forecast area may get 15 to 20 cm of precipitation. No overnight freeze and freezing levels may go up to 1600m. Winds light, gusting to moderate from the south west.Saturday: Cloudy with flurries. 15 to 20 cm of precipitation in the forecast for the region, daytime freezing level around 1500m, overnight freezing levels will drop close to valley bottom, winds, light to moderate from the south west.Sunday: Cloudy with flurries, trace of precipitation possible, freezing level may rise to 1700m, winds light gusting to moderate from the south west.

Avalanche Summary

Reports of large avalanches were down from yesterday, but we are still getting reports of loose dry and loose wet avalanches from steep alpine terrain. One size 2 avalanche triggered by a cornice failure. Sluffing in steep terrain is being reported on all aspects.A low probability, but high consequence avalanche problem exists in the Columbia regions. Highly destructive and unpredictable avalanches are possible during these spring conditions. Smaller avalanches have been reported stepping down to old, deeply buried weak layers and producing very large avalanches.

Snowpack Summary

Recent warm temperatures have resulted in good settlement and bonding of the storm snow from earlier in the week. Reports of human-triggered avalanches have diminished. Three persistent weaknesses contribute to a highly variable snow pack with the possibility of triggering deeper instabilities. The mid-March sun crust/surface hoar layer down 50-80cm still has potential for human-triggering in isolated areas. The early-March crust/facet/surface hoar layer down around 80-120cm has become less susceptible to triggering by light loads, but still has the ability to produce large avalanches, we continue to hear reports of avalanches stepping down to this layer. The mid-February crust/facet/surface hoar layer is typically down at least 1.5m and direct triggering has become unlikely. However, large loads like cornices or smaller avalanches picking up mass might still trigger this layer and produce very large avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent storm snow may still be reactive to human triggers on wind loaded features. A small avalanches could easily injure a rider.  Pay close attention to solar input, especially late in the afternoon.  Large mature cornices can fall at any time.
Pay attention to overhead hazards like cornices.>Be cautious as you transition into wind affected terrain.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
Weak layers buried earlier this month remain reactive to triggering on convex slopes, south aspects, and steep alpine terrain. A small avalanche might provide enough mass to trigger a persistent weakness and result in a highly destructive avalanche .
Minimize exposure to sun exposed slopes when the solar radiation is strong.>Use conservative route selection, stick to moderate angled terrain with low consequence.>Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Highly destructive avalanches are expected to continue. The variable nature of this problem makes it difficult to predict exactly when and where avalanches are going to occur. A cornice failure, or sun and warm temperatures may 'wake-up' weak layers.
Be aware of thin areas that may propogate to deeper instabilites.>Local knowledge of slopes that have yet to avalanche is valuable for knowing which slopes to avoid.>Avoid large convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Apr 4th, 2014 2:00PM