Avalanche Forecast

Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack.

Wednesday night: Clearing. Moderate northerly wind. Alpine temperatures around -9. Freezing level valley bottom.

Thursday: Mix of sun and cloud. Moderate to strong northwest wind. Alpine high temperatures around -7. Freezing level 1000 m.

Friday: Mostly cloudy. Strong northwest wind shifting southwest. Alpine high temperatures around -5. Freezing level 1000 m.

Saturday: Mostly cloudy. Strong southwest wind. Alpine high temperatures around -5. Freezing level 1000 m.

We are awaiting observations of avalanche activity during and since the storm. Little was reported Tuesday due to poor visibility. Below treeline observations included pinwheeling on the moist surface and size 1-1.5 wind slabs size triggered naturally and by ski cuts on north to west aspects 1000-1300m near the southwest border of the region. 

Reports of avalanche activity on Monday come primarily from the southwest of the region, near the Howson range, including:

• a natural size 2 wind slab on an east aspect around 2000 m
• explosive-triggered cornices and wind slabs size 1-3
• natural loose wet avalanches out of steep rocky solar aspects
• skier triggered size 1 loose dry out of steep terrain.

Touchy storm slab conditionshave been observed since Saturday at Sinclair. Reactive wind slabs were reported in the Hudson Bay Mountain area on Friday prior to the storm.

Tuesday's storm dropped 15-20 cm of new snow over the region, depth varying throughout the region and with elevation. After a lull toward the end of the storm, wind is forecast to pick up again from the northwest on Thursday, likely forming fresh wind slabs in lee terrain features at upper elevations. At lower elevations, the snowpack is moist as recent precipitation fell as rain.

Buried 50 cm deep, a layer of spotty surface hoar crystals may exist on sheltered north aspects as well as a melt-freeze crust on south aspects. Recent observations suggest warm temperatures have aided bonding at this interface. 

The mid and lower snowpack is reported as well settled and strong in most areas. However, weak facets exist at the base of the snowpack in the more shallow snowpack zones within much of the region and always have the potential of being triggered on steep, rocky slopes with a shallow or thin to thick snowpack; especially with large loads such as a cornice fall.

• Pay attention to the wind, once it starts to blow fresh sensitive wind slabs are likely to form.
• Wind slabs are most reactive during their formation.
• Seek out sheltered terrain where new snow hasn't been wind-affected.