Avalanche Forecast
Issued: Apr 22nd, 2018 4:32PM
The alpine rating is Loose Wet, Cornices and Wind Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Low - Due to the number of field observations
Weather Forecast
Monday: Mainly sunny. Light southeast winds. Freezing level to 2200 metres and rising overnight. Alpine high temperatures around 0.Tuesday: Mainly sunny. Light south winds. Freezing level to 2700 metres with alpine high temperatures around +3. Weak overnight cooling.Wednesday: Mainly sunny. LIght to moderate southwest winds. Freezing level to 3100 metres with alpine high temperatures around +5. Weak overnight cooling.
Avalanche Summary
Several smaller (size 1.5) natural wind slab avalanches were observed in the region on Saturday. These occurred primarily on northwest aspects above 2400 metres.Reports from Thursday were limited to a couple of size 2 storm and wind slabs, 30 and 50 cm deep, respectively. The storm slab released naturally while the wind slab was ski cut from a steeper north aspect in the alpine.Tuesday's reports included observations of numerous natural wind slab release from size 1-2 on north through east aspects in the alpine. A skier triggered size 2 storm slab resulted in a near miss. Another recent very large (size 3.5) storm slab was also observed to have released on a large, wind-loaded alpine feature. Observations from late last week also showed a pattern of heightened cornice failure activity. Looking forward, a period of increasing warming, full sun, and warm overnight temperatures will be maintaining elevated chances of cornice and loose wet avalanche activity.
Snowpack Summary
10-15 cm of new snow has been blown into wind slabs on a variety of aspects due to variable strong winds. The wind affected snow overlies a melt freeze crust found on the previous surface on all but north aspects above about 2200 metres. Below it, about 50-70 cm of settled storm snow overlies a supportive crust which shares similar distribution to the upper crust.Within this storm snow there are a few different crusts with the shallowest of these (down about 20-40 cm) now a limited concern as recent warm temperatures have promoted settlement and bonding in the upper snowpack.With warm daytime temperatures and poor overnight recovery of cold temperatures, there is some lingering concern around the mid-March weak layer in the alpine where it is found 90 to 120 cm deep. This buried crust/surface hoar layer was widely reactive but is now trending towards dormancy. It should be kept in the back of our minds for its capability to produce large avalanches should it be triggered with a heavy load such as a cornice collapse.Deeper persistent weak layers from December and January are generally considered dormant at this time but may be reactive to very large triggers.
Problems
Loose Wet
Aspects: North, North East, East, South East.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 23rd, 2018 2:00PM