Avalanche Forecast

Archived

Apr 9th, 2025–Apr 10th, 2025

Alpine

Natural avalanches unlikely, human triggered possible.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches unlikely.

Treeline

Natural avalanches unlikely.

Below Treeline

Below Threshold.

Regions

Yukon, Tutshi, Wheaton, White Pass East, White Pass West, Haines Pass.

Be cautious when transitioning into wind loaded terrain.

Recent snow and wind have built small wind slabs in lee features at upper elevations.

Confidence

Moderate

Avalanche Summary

A cornice triggered slab was reported in the Big Y area of the whitepass this past weekend.

If you observe an avalanche, please share your observations on the Mountain Information Network.

Snowpack Summary

Up to 10 cm of new snow is now resting on wind pressed surfaces and wind slabs in open terrain while leaving 15-25 cm of settled surface snow in sheltered areas. A melt-freeze crust covers most solar slopes as well as northerly slopes up to 1250 m.

Below 1100 m the snowpack is wet with no structure.

A buried surface hoar or crust layer, 40 to 60 cm deep, is variable in distribution.
A December crust with facets, 100 to 150 cm deep on all aspects up to 1750 m, has shown no significant test results.

Snow depth ranges from 100 cm at highway elevations to over 300 cm in the alpine.

Weather Summary

Wednesday Night

Partly clear with flurries. 20 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 800 m.

Thursday

Mix of sun and cloud with flurries. 30 to 40 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 900 m.

Friday

Mix of sun and cloud with up to 5 cm of snow. 10 to 30 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level 700 m.

Saturday

Mostly cloudy with flurries. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level 700 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avalanche activity is unlikely when a thick melt-freeze crust is present on the snow surface.
Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
Pay attention to cornices and give them a wide berth when traveling on or below ridges.

Problems

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.

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.