Avalanche Forecast

Issued: Jan 9th, 2015 4:00PM

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

deryl kelly, Parks Canada

Jasper.

Keep your head up folks. Rapid variations in temperature and solar effect is waking up a touchy storm slab.

Summary

Weather Forecast

Steady as she goes! No expected dramatic changes in the weather. Mainly overcast skies and light snow expected over the day Saturday.

Snowpack Summary

Overall, as we continue to explore areas outside the normally accessed skiing, field teams are finding a weak snowpack. The Dec 20 facet/surface hoar layer is out there. It is proving to be very sensitive to fluctuations in temp and solar radiation and is showing exceptional propagating properties for having only a weak soft storm slab over it.

Avalanche Summary

An avalanche cycle is being reported from field teams with multiple slides, up to sz 3 on south to westerly (solar) aspects over the last 2 days. A dramatic temperature inversion at around 2500ms (cold air low/warm above) is affecting the slopes and seems to have enough punch to initiate the natural activity.

Confidence

Timing or intensity of solar radiation is uncertain

Problems

Storm Slabs

Recent storm snow has settled into a soft slab which overlies a weak layer of facets and surface hoar. Temperature fluctuations and direct solar radiation may well lead to an increased likelihood of avalanches.

Be careful with wind loaded pockets while approaching and climbing ice routes.Watch for whumpfing, hollow sounds, and shooting cracks.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Deep Persistent Slabs

This weak layer exists below a variable mid-pack at treeline and sub-alpine elevations. Large loads such as a cornice collapse or surface slides could still possibly trigger this deep persistent weakness.

Carefully evaluate and use caution around thin snowpack areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 10th, 2015 4:00PM