Avalanche Forecast

Archived

Jan 13th, 2025–Jan 14th, 2025

Alpine

Natural and human triggered avalanches likely.

Treeline

Natural and human triggered avalanches likely.

Below Treeline

Below Threshold.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Below Threshold.

Alpine

Natural avalanches possible, human triggered probable.

Treeline

Natural avalanches possible, human triggered probable.

Below Treeline

Below Threshold.

Regions

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

6:15 AM Update: Today is a good day to avoid avalanche terrain; natural avalanches are expected.

Confidence

Low

Avalanche Summary

We expect natural avalanche activity during today's storm.

On Friday large and very large (size 2-3) natural and explosive-triggered avalanches were observed along the Klondike highway corridor.

On Wednesday and Thursday our field team observed size 1-2 storm slab avalanches and experienced whumpfing. See photo below.

Check out this MIN report from last week.

Snowpack Summary

Up to 70 cm of snow fell in the alpine last week and up to 30 cm more is forecast until Thursday afternoon. Rain is expected below around 1000 m. Most of the snowfall occurred near White Pass, with significantly less in the Wheaton and Tutshi areas. All this storm snow may bond slowly, as it rests on a base of weak facets and, in some isolated areas, on surface hoar.

A persistent weak layer consisting of a crust with 20 cm of facetted snow above it is buried 60 to 90 cm, and extends up to 1700 m. Some storm slabs last week stepped down to this crust, triggering large avalanches.

Total snow depths are around 100–180 cm at treeline.

Weather Summary

Monday Night

Cloudy with snow beginning in the evening 10 to 25 cm. 60 to 80 km/h southwest ridgetop wind. Treeline temperature -1 °C.

Tuesday

Cloudy with snow 5 to 15 cm, with precipitation amounts becoming less the further you go inland. 50 to 80 km/h southwest ridgetop wind. Treeline temperature -4 °C.

Wednesday

Mostly cloudy with afternoon clearing. 20 to 40 km/h south ridgetop wind. Treeline temperature -10 °C.

Thursday

Clearing. 20 to 40 km/h northwest ridgetop wind. Treeline temperature -15 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

Avoid avalanche terrain during periods of heavy loading from new snow, wind, or rain.
Fresh snow rests on a problematic persistent slab, don't let good riding lure you into complacency.
Storm slabs in motion may step down to deeper layers resulting in large avalanches.
Remote triggering is a concern; avoid terrain where triggering overhead slopes is possible.

Problems

Storm Slabs

Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.

Persistent Slabs

Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.