Avalanche Forecast

Issued: Mar 1st, 2018 4:43PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs.

jmcbride, Avalanche Canada

Northwest Inland.

New snow and strong wind will form deep and touchy slabs particularly at upper elevations. Be especially way of wind-loaded, leeward and cross-loaded slopes and pay attention to overhead hazards, like cornices, especially once the sun pokes out.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

TONIGHT: Light flurries. Accumulation trace. Ridge wind strong, east. Temperature near -12. Freezing level valley bottom.FRIDAY: Mix of sun and cloud. Ridge wind light to moderate, northeast. Temperature near -12. Freezing level valley bottom. SATURDAY: Mostly sunny. Ridge wind light, northeast. Temperature near -15. Freezing level valley bottom. Alpine inversion.SUNDAY: Mostly sunny. Ridge wind light, northwest. Temperature near -10. Freezing level valley bottom. Alpine inversion.

Avalanche Summary

Storm snow and moderate to strong winds have grown cornices and formed widespread storm slabs in the alpine and at treeline elevations.On Wednesday there were reports of numerous natural wind slab and cornice releases up to size 3 triggered by rapid wind-loading. These reports were on predominantly north through east aspects above 1800 m. There were also reports of skier triggered avalanches up to size 2, including a close call north of Kispiox where the 4th skier on the slope triggered a buried wind slab on an east aspect at 1450 m.Tuesday there were reports from northern parts of the region of loose dry storm snow releases up to size 1.5 in steep terrain as well as a skier triggered storm slab (size 1) on steep, southeast-facing, roll that failed on a buried sun crust.On Monday there was a report of a natural size 2 storm slab release on a east aspect below treeline feature that failed on facets buried by recent storm snow. Skiers also reported triggering small storm slab releases on steep convex rolls below treeline.

Snowpack Summary

Approximately 40-60 cm of new and recent storm snow now covers old, hard wind slabs and scoured surfaces in many exposed areas while in wind-sheltered terrain, sun crusts or dry facets sit below the recent storm snow.A crust/surface hoar layer buried mid-January is now roughly 80 - 140 cm below the surface, and still has the potential to be triggered from a thin snowpack spot, or with a large trigger like cornice fall.Facets at the base of the snowpack could also possibly be triggered from shallow snowpack areas.

Problems

Storm Slabs

Strong wind is redistributing storm snow forming slabs particularly at upper elevations and on open features at and below treeline. Expect these slabs to be sensitive to light triggers and could be easily triggered by the weight of a person.

Avoid lee areas in the alpine and treeline. Storm snow and wind will form touchy slabs.Give cornices a wide berth when travelling on or below ridges.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 2nd, 2018 2:00PM