Avalanche Forecast

Issued: Apr 9th, 2018 4:23PM

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

mconlan, Avalanche Canada

South Coast.

Expect changing weather on Tuesday: warm air that will cool over the day, intense rain switching to snow, strong winds, and afternoon sun breaks. Warming will weaken the snow and new snow will form fresh slabs. Be cautious with these rapid changes.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

TUESDAY: Morning precipitation with afternoon clearing, accumulation 20 to 30 mm rain switching to snow at higher elevations mid-morning, strong to extreme southwest winds, treeline temperature 4 C, freezing level 2600 m dropping to 1200 m over the day.WEDNESDAY: Cloudy with snowfall, accumulation 20 to 30 cm, moderate to strong south winds, treeline temperature -1 C, freezing level 1200 m.THURSDAY: A mix of sun and cloud, light west winds, treeline temperature -2 C, freezing level 1100 m.

Avalanche Summary

We have received very little information on avalanche activity for this region. From the little we have heard, it was generally easy to initiate large wet loose avalanche in steep terrain below treeline on the weekend but this activity decreased into Monday. Forecasted high freezing levels and rain should mean that the likelihood of triggering avalanches is on the rise.We would very much appreciate it if you spend a moment to submit any observations you have to the Mountain Information Network here, even if it is just a photo. Thanks!

Snowpack Summary

Warm air temperatures are moistening the weekend’s 40 to 100 cm of storm snow at treeline and alpine elevations, which sits above a thick crust. Tuesday’s precipitation will continue to moisten the snow where it falls as rain and build new slabs where it falls as snow. It is difficult to predict where and when rain will switch to snow, but expect the transition to happen midday on Tuesday, after which point most precipitation will fall as snow in the region above 1000 m.At below treeline elevations, a spring snowpack exists. Rain on the weekend saturated and weakened the upper snowpack. Forecasted rain will continue this trend. The mid and lower snowpack are strong.

Problems

Storm Slabs

Older slabs will weaken with the warming and rain and could run full-path in the north of the region. Watch for new slabs that will form when rain switches to snow. Snow will fall with strong southwest winds, so expect thicker slabs in lee features.

Pay attention to overhead hazards like cornices, which could trigger slabs on slopes below.Use ridges or ribs to avoid pockets of wind-loaded snow.Observe for the bond of new snow with the old surface before committing into avalanche terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Loose Wet

Warm temperatures, rain, and afternoon sun could rapidly weaken the snow surface. This is particularly the case for the north of the region, which hasn't seen as much rain or warming as the south. Avoid overhead exposure.

Avoid steep slopes when air temperatures are warm, it is raining, or the solar radiation is strong.Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Apr 10th, 2018 2:00PM