Avalanche Forecast
Issued: Apr 18th, 2019 3:51PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet.
cgarritty,
Avalanche Canada
Strong winds and increasing rain will make for less than ideal travel conditions on Friday. Loose wet avalanche activity may be especially pronounced on high north aspects.
Summary
Confidence
Weather Forecast
Thursday night: Increasingly cloudy. Moderate to strong southwest winds. Freezing level remaining near 2700 metres.
Friday: Cloudy with scattered showers and 1-3 mm of rain accumulating, increasing overnight. Moderate to strong southwest winds. Alpine high temperatures around +5 with freezing levels to 2700 metres, dropping to 1800 overnight.
Saturday: Cloudy with easing wet flurries leaving a possible trace to 5 cm of wet new snow at higher elevations. Light east winds. Alpine high temperatures around -1 with freezing levels to 2000 metres.
Sunday: Sunny with cloudy periods. Light southeast winds. Alpine high temperatures around +3 with freezing levels to 2400 metres.
Avalanche Summary
On Sunday skier triggered avalanches were widespread on north through east facing slopes in the alpine and down into treeline too.
A natural avalanche cycle occurred Saturday night, the highlights were storm slabs up to size 2 on northeast facing alpine terrain around 1700 m. A natural cornice failure was observed from a north facing ridgeline which subsequently triggered a size 2.5 storm slab involving the new snow. Control work produced storm slabs to size 2. We received a great MIN report of a small storm slab from Saturday morning in the first hours of the storm.
Snowpack Summary
Recent sun and temperature crusts are likely to be found on the surface on solar aspects and below the alpine, having formed above the 30 cm of dense snow from the past weekend's storm. In most areas, this storm snow sits above a widespread supportive crust. By Friday evening, light rain is expected to create moist snow conditions on all aspects and elevations.
North facing alpine terrain may still hold a cold, dry snowpack and as a result may see more pronounced loose wet activity as it rain saturates it for the first time. High elevation north facing terrain also harbours a deeply buried layer of facets. Although unlikely, human triggering of persistent slabs on this layer may still be possible in rocky alpine terrain with shallow or variable snowpack depth.
Below treeline the snowpack has melted or is isothermal.
Problems
Loose Wet
Steady warm temperatures and light rain will promote loose wet avalanche activity in the storm snow from last weekend. High elevations that haven't yet seen a melt cycle are the most prone. Conditions will deteriorate over the day as rain increases.
- A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
- Wet slab releases may occur as rain saturates slabs that are poorly bonded to the underlying crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Apr 19th, 2019 2:00PM
