Avalanche Forecast

Issued: Mar 28th, 2016 4:49PM

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

Ruari Macfarlane, Parks Canada

Waterton Lakes.

A widespread natural avalanche cycle is expected on Tuesday. Later in the forecast period, natural activity will taper off on cooler (high and shady) slopes, but conditions may be ripe for human triggering on many slopes.

Summary

Weather Forecast

A strong upslope moisture feed is causing heavy snowfall, easing Tuesday morning, then clearing. Strong NE winds develop at treeline and alpine elevations tonight . Around midday Tuesday, these ease to Moderate, then Light. Freezing Levels remain near valley floor until Wednesday, when above freezing temps at Treeline keep hazard elevated.

Snowpack Summary

40-55cm of new snow arrived today (Sunday), and will continue to fall through midday Tuesday. The rapid rate of loading, and strong NE winds forecast overnight will consolidate this snow into a widespread Storm Slab problem.

Avalanche Summary

Heavy snowfall and poor visibility prevented observations of any avalanche terrain today. New snow was stubborn to sluffing on steep road cuts; however small Storm Slabs were observed peeling off many steep surfaces at valley bottom, such as roofs. A nearby operation reported very touchy conditions, including large (Size 2) Loose Dry avalanches.

Confidence

Forecast snowfall amounts are uncertain

Problems

Storm Slabs

These will be widespread, but most prevalent on S and W aspect lee slopes at Alpine and Treeline elevations. Sensitivity will increase with slope angle, and especially if temperatures approach 0 degrees, and/or / during strong sun.

Keep an eye out for reverse loading created by an upslope storm.Avoid avalanche terrain during periods of of strong sun, or heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Dry

Natural Loose Dry avalanches are likely in steep terrain on Tuesday, while human triggered sluffing in more sheltered terrain will remain likely throughout the forecast period.

Avoid travelling under cliffs that are exposed to sluffing from above.Sluffs will be easy to trigger in steep terrain that is sheltered from the wind

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

On Wednesday and Thursday, warming temperatures, and some sun, will persuade the mountains to shed their new load of snow. Natural Loose Wet avalanches will be likely out of steep terrain, and may run far/fast on a crust.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.

Aspects: North, North East, East, South East, South.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 31st, 2016 4:00PM