Avalanche Forecast
Issued: Mar 8th, 2018 4:24PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeDirect sun is likely to weaken surface snow layers and give cornices a bit of an extra nudge. Avalanche danger may spike higher than forecast on sun-exposed slopes.
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain on Friday
Weather Forecast
FRIDAY: Cloud clearing. Treeline temperature near -8. Light winds.SATURDAY: Sunny. Treeline temperature near -3. Light winds.SUNDAY: Mainly sunny. Treeline temperature near -1. Light winds.
Avalanche Summary
On Wednesday, a few large persistent slabs failed naturally, one with a solar trigger and a couple triggered by icefall. A few small loose and slab avalanches were also reported.A few large (size 2-3) persistent slabs also failed early this week, both naturally and with a remote trigger. These were reported as failing on the February persistent weak layers on south to west aspects, mostly in the east of the region.Avalanche activity is expected to increase as we move into a period of intense sun and prolonged warming. Predictable loose wet avalanches from steep, sunny terrain should be easy to manage. The trickier beast will be when warmth penetrates into the snowpack and starts tickling deeper persistent weak layers. I'd avoid exposure to large sunny features and keep well away from corniced slopes over the next few days.
Snowpack Summary
Around 20 cm new snow has formed storm slabs and variable thin wind slabs which overlie sun crusts on solar aspects.A couple of layers buried in mid-late February (down around 50-100 cm) are variably reactive, but both have the potential to create surprisingly large avalanches if triggered. Initially, these interfaces were most reactive on solar aspects, where they present as buried sun crusts. However, persistent slabs have been triggered on shady aspects too, where surface hoar and/or facets exist.Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with forecast warming, a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets linger at the base of the snowpack.
Problems
Storm Slabs
New snow and wind have formed variable storm slabs and loose snow conditions. These could be triggered by solar radiation, cornice fall or the weight of a person.
Use ridges or ribs to avoid pockets of wind loaded snow.Give cornices a wide berth when travelling on or below ridges.Use caution on open slopes and convex rolls
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Persistent slabs are most likely to be triggered with a large load like cornice fall; or by a person in a thin or variable-depth snowpack spot. Solar warming could also wake up these sleeping beasts.
Avoid convoluted terrain with variable or shallow snow depths and multiple trigger points.Pay attention to overhead hazards like cornices which could trigger persistent slabs.Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 9th, 2018 2:00PM