Conditions may change quickly in the spring. Even brief periods of sun can trigger pushy loose wet avalanches or promote destructive cornice falls.
Summary
Confidence
Moderate - Timing or intensity of solar radiation is uncertain on Tuesday
Weather Forecast
On Tuesday expect generally overcast skies with isolated flurries. On Wednesday a Pacific system will bring 10-20cm of new snow to the region. Light flurries are forecast for Thursday. Ridgetop winds will be light on Tuesday, and then become moderate and southwesterly with Wednesday's precipitation. Freezing levels should hover between 1200 and 1300m for the forecast period.
Avalanche Summary
On Friday, there was an anomalous size 2.5 slab avalanche on an unsupported rocky face on the northwest corner of Mt Fissile (in the Fitzsimmons Range) at about 1900m. Although the sliding layer is unknown, the avalanche was thought to have been triggered by warming. Over the past week there have also been numerous reports of solar-triggered cornice falls. Some cornice falls have been large (up to size 3), but most have only entrained surface snow. Explosives control ion Monday triggered storm slabs and cornice falls to size 2 in mostly alpine terrain.
Snowpack Summary
On Sunday night the region received between 12 and 30cm of new snow with highest amounts falling in the Southern Garibaldi/ Brandywine parts of the region. Moderate southerly winds formed soft slabs which seemed most reactive in lee alpine terrain. The new snow overlies a sun crust on sun-exposed slopes, dry settled powder on shady slopes and moist snow below 1800m. Below the new snow the snowpack is strong and well-settled throughout with no notable persistent weaknesses. Cornices are huge and fragile.
jlammers,
Avalanche Canada
