Avalanche Forecast
Issued: Mar 7th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs.
ahanna,
Avalanche Canada
New snow and moderate wind overnight will drive fresh wind slab formation at upper elevations. Watch for reactivity in pockets of freshly wind-loaded snow especially below ridge crests and roll-overs.
Summary
Confidence
Weather Forecast
The region will catch the western extent of an upslope system, meaning greatest snowfall amounts for the Flathead.
Monday night: 5-15 cm of new snow. Light to moderate northeast ridgetop wind. Alpine temperature around -10 °C. Freezing level dropping to valley bottom.
Tuesday: Mostly cloudy. Light northeast wind. Alpine high around -10 °C.
Wednesday: A mix of sun and cloud. Light northwest wind. Alpine high around -12 °C.
Thursday: Mostly sunny. Moderate northwest wind. Alpine high around -7 °C.
Avalanche Summary
On Monday, small, fresh wind slabs were reactive to ski cuts.
Over the weekend near Fernie, storm slabs were reactive to explosives size 2-3 on northeast aspects in the alpine and upper treeline. We received several reports of rider triggered size 1 storm slabs in the alpine and loose dry avalanches up to size 1.5 around treeline.
On Friday, storm slabs up to size 2.5 ran naturally in addition to rider and explosive triggers.
Between Thursday and Sunday, numerous solar triggered loose wet avalanches were reported up to size 1.5 in steep terrain on east to south aspects in the alpine and all aspects below treeline.
Snowpack Summary
New snow blankets previous storm snow and a sun/temperature crust on solar aspects and below 1800 m.
A rain crust buried somewhere in the 50-100 cm of last week's storm snow has been found as high as 2100 m and is well bonded to surrounding snow. At up to 10 cm thick, it effectively bridges any deeper instabilities in the snowpack.
In areas and elevations where the rain crust is thinner, we continue to monitor the potentially weak interface below last week's storm snow, 50-100 cm deep. These old surfaces include sun and freezing rain crusts as well as weak faceted crystals on shaded aspects.
The lower snowpack is generally well consolidated, with a crust/facet layer from early December found near the ground. It is currently considered dormant but could become active later this season.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
- Dial back your terrain choices if you are seeing more than 20 cm of new snow.
Problems
Wind Slabs
The most likely places to trigger a wind slab include unsupported convex roll-overs and where recent snow sits over a crust.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 8th, 2022 4:00PM
