Sea to Sky Avalanche Forecast
Apr 22nd, 2019 4:01PM
Wind slabs may react to human triggers around ridges and lee features. Loose wet avalanches remain a concern, best to travel early and avoid moist/wet slopes.
MONDAY NIGHT: Cloudy with isolated flurries, trace to 5 cm, moderate southwest wind, alpine temperature -2 C, freezing level 1600 m.
TUESDAY: Cloudy with isolated flurries, light to moderate west-southwest wind, alpine temperature -1 C, freezing level 1800 m.
WEDNESDAY: Mix of sun and clouds, light southwest wind, alpine temperature -1 C, freezing level 1800 m.
THURSDAY: Mostly cloudy, light southeast wind, alpine temperature +1 C, freezing level 2200 m.
On Saturday morning around the Whistler Backcountry, a natural wet loose avalanche cycle to size 2 was observed on all aspects from 1900-2200m. Wet slab avalanches to size 3 were observed on loaded northerly features in the alpine. Natural cornices failures to size 2 were also observed and explosives triggered cornices size 2-2.5. Further south in the region, cornices failing naturally triggered large (up to size 3) slab avalanches on the slopes below.
On Friday morning, explosives triggered two wet loose size 2 avalanches and several size 2 cornices, in some cases cornices triggered wet slab avalanches to size 2 on the slopes below. One natural storm slab avalanche was observed on a north aspect, the likely trigger a natural cornice failure on the slope.
On Thursday night and into Friday, a loose wet avalanche and cornice cycle occurred in the region during the storm, producing small to large avalanches (size 1 and 2). Most of the avalanches occurred in the alpine as well as treeline.
Flurries Monday accompanied by south-southwesterly winds accumulated up to 10 cm at upper elevations. In the alpine, cold wind-affected snow is holding onto northerly aspects, and a crust has developed on solar slopes. Warm overnight temperatures are preventing strong crust recovery as you lose elevation, thin crusts will break down quickly during the day increasing the likelihood of loose wet avalanches.
Below treeline the snowpack is saturated and rapidly melting.
South-southwesterly winds have redistributed loose snow, be cautious of more reactive deposits around ridges and in lee terrain above 2000 m. Cornices may be touchy, give them plenty of space.
- Be careful with wind-loaded pockets, especially near ridge crests.
- New cornices will be weak and could trigger wind slabs on slopes below.
Aspects:North, North East, East, South East, West, North West.
The likelihood of loose wet avalanches will depend on the extent of overnight crust recovery and the pace at which the warms through the day.
- Avoid terrain traps such as cliffs and gullies that increase the consequence of small avalanches.
- Minimize overhead exposure and avoid steep slopes during periods of strong sun.
Valid until: Apr 23rd, 2019 2:00PM