Avalanche Forecast

Issued: Apr 6th, 2018 3:35PM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Storm Slabs and Loose Wet.

mconlan, Avalanche Canada

South Coast.

More precipitation is forecasted for Saturday, with snow at high elevations and rain below. Be cautious of periods of rapid precipitation loading, as avalanche activity may increase.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

SATURDAY: Cloudy with snow at higher elevations and rain below, accumulation 20 to 30 mm water equivalent, strong southerly winds, treeline temperature 3 C, freezing level 1600 m.SUNDAY: Mostly cloudy with early-morning precipitation, accumulation 10 to 20 mm water equivalent, light westerly winds, alpine temperature 1 C, freezing level 1400 m.MONDAY: Mostly cloudy, light southwesterly winds, alpine temperature 2 C, freezing level 1600 m.

Avalanche Summary

On Thursday, it was easy to initiate large wet loose avalanche in steep terrain below treeline. The avalanches were generally slow but ran far.

Snowpack Summary

Around 15 to 60 mm of rain fell on the snowpack up to around 1700 m on Thursday and Friday, with precipitation as snow above. More of the same is forecasted for Saturday. In alpine terrain, the snow will create new storm slabs. This snow overlies variable surfaces including crusts and facets, which are more likely to be problematic on shady aspects. The snowpack below this is generally strong.At treeline and below treeline elevations, a spring snowpack exists. Rain is saturating and weakening the upper snowpack, allowing for loose wet avalanches. This wet snow may freeze overnight at higher elevations with cool temperatures. The mid and lower snowpack are strong.

Problems

Storm Slabs

Snowfall at higher elevations has formed new slabs. More snow is forecasted for Saturday, which will build thicker slabs. Observe for the bond of new snow with the old surface before committing into avalanche terrain.

Minimize exposure during periods of heavy loading from new snow, wind or rain.Use ridges or ribs to avoid pockets of wind-loaded snow.Pay attention to overhead hazards like cornices, which could trigger slabs on slopes below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

Precipitation will fall as rain at lower elevations, saturating and weakening the upper snowpack. Watch out in steep and gullied terrain, where small avalanches can build and have severe consequences.

Use extra caution on slopes if the snow is moist or wet.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.Best to avoid avalanche terrain during periods of heavy loading from rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 7th, 2018 2:00PM