Avalanche Forecast

Issued: Feb 8th, 2016 8:01AM

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

pgoddard, Avalanche Canada

Purcells.

Skyrocketing temperatures are expected to weaken surface snow layers, make cornices extra fragile and possibly wake up deeply buried weak layers.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

A strong ridge of high pressure is expected to bring sunny skies above valley cloud. Valley cloud tops should be around 1500 m. A warm southerly flow causes alpine temperatures to rise well above 0, with peak warming and sunshine on Tuesday. Some light precipitation may arrive on Thursday with the passage of a warm front.For more details check out http://www.avalanche.ca/weather.

Avalanche Summary

A natural and artificially-triggered cycle of size 1-3 avalanches occurred on Saturday in response to new snow and very strong winds. The largest events were in the northern Purcells/ Dogtooth Range. These are suspected to have failed on the early January persistent weak layer. Numerous persistent slabs have been triggered in the north over the last couple of weeks. On Friday, a snow cat triggered a size 2 persistent slab on a SE aspect near 2300 m near Golden. Last Saturday, a size 3 sledder-triggered avalanche occurred in the Gorman Creek riding area. Around the same time, a skier triggered a size 3.5 persistent slab a few drainages to the south of Gorman Creek on a north-facing alpine slope. Forecast warming may increase the reactivity of the persistent slab.

Snowpack Summary

Warm temperatures and sunshine are expected to weaken and moisten surface snow layers. Strong to extreme winds on Saturday created wind slabs and cornices in many areas, and scoured north and west-facing alpine slopes. The early January surface hoar/ facet layer is typically down 70-90 cm. Recent very large avalanches have been failing on this interface in the north of the region (see avalanche discussion). In general, the lower snowpack below this layer is well settled and strong, apart from some thin snowpack areas where basal facets exist.

Problems

Loose Wet

Strong sunshine and warm temperatures are expected to weaken surface snow layers and cause loose wet avalanches or wet slabs.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be aware of what is above you at all times.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Wind Slabs

Recently formed wind slabs may still be able to be triggered by the weight of a person. Cornices are likely to be fragile in the hot weather.

Pay attention to overhead hazards like cornices.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Travel on ridges to avoid freshly wind loaded features. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

A deeply buried weak layer can still be triggered in some places, creating very large avalanches. Forecast warming may increase the sensitivity of this problem.

Be cautious around open slopes and convex rolls at and below treeline where buried surface hoar may be preserved. Big alpine features are also suspect.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 5

Valid until: Feb 9th, 2016 2:00PM