Avalanche Forecast

Archived

Mar 24th, 2021–Mar 25th, 2021

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely, human triggered possible.

Below Treeline

Below Threshold.

Regions

Yukon.

Expect to find an array of small but reactive new wind slabs and more stubborn older slabs as you enter exposed terrain. Or choose sheltered areas for better skiing/riding quality. Be ready to step back if snowfall exceeds the forecast.

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

Wednesday night: Becoming clear. Light northwest winds, increasing into the morning.

Thursday: Becoming cloudy again with light furries beginning with a trace of new snow, increasing a bit overnight. Moderate southwest winds. Alpine high temperatures around -9.

Friday: Cloudy with flurries bringing up to 5 cm of new snow, continuing overnight. Light to moderate southwest winds. Alpine high temperatures around -8.

Saturday: Cloudy with continuing flurries bringing up to 5 cm of new snow. Light to moderate southwest winds. Alpine high temperatures around -11.

Avalanche Summary

A MIN report from the White Pass area on Monday showed some new wind slab formation and reactivity as a result of recent northerly winds. This process likely sustained over the last couple of days of relatively consistent wind and lots of snow available to blow around.

Looking forward, a shift back to elevated southwest winds with light snowfall should keep wind slab problems active across varied aspects.

Snowpack Summary

Around 20 cm of recent snow overlies previous surfaces, including a hard melt-freeze crust on south aspects, widespread wind effect in the alpine and in wind-exposed terrain around treeline, and settled dry snow in sheltered terrain at treeline elevations. Loose surface snow was likely blown into new wind slabs by elevated southwest winds on Tuesday.

There are no deeper concerns around White Pass.

Substantial spatial variability exists in the snowpack around the Tutshi Lake/Paddy Peak area. Terrain should be assessed on a slope by slope basis, as lingering snowpack weaknesses may still exist.

The Wheaton's continental snowpack is dominated by hard wind slabs overlying sugary facets and depth hoar. It's an untrustworthy snowpack structure that requires good terrain selection and travel habits.

Terrain and Travel

Avoid exposure to slopes that have cornices overhead.
In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.