Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain.

Saturday night: Cloudy with continuing snowfall bringing another 10-20 cm of new snow. Extreme southwest winds.

Sunday: Cloudy with continuing snowfall bringing another 5-15 cm and two day snow totals to 30-70 cm. Moderate to strong west winds easing and shifting north over the day. Alpine temperatures cooling to around -11 over the day as freezing levels return to valley bottom.

Monday: A mix of sun and cloud. Light to moderate west winds. Alpine high temperatures around -13.

Tuesday: Cloudy with scattered flurries and less than 5 cm of new snow. Moderate west winds. Alpine high temperatures around -7.

We don't yet have observations from Saturday's storm in the region, but light initial accumulations at weather stations suggest its impacts may be delayed to Saturday night and Sunday. Continuing snowfall and high winds over this period should make for active avalanche conditions on Sunday. The west slope of the region is still where the greatest accumulations are expected.

Explosives control in the wake of the last storm yielded many storm and wind slabs in the size 2-2.5 range in the Table River Valley on Thursday, with one size 3 (very large) release. Evidence of Wednesday's widespread natural cycle was observed during the same mission, with many more size 3 avalanches noted on a greater range of terrain.

New snow totals from the weekend storm are expected to reach 30-70 cm by end of day on Sunday. Amounts may be lighter in typically lower snowfall areas on the east slope. Much of this snowfall is forecast to be accompanied by extreme south and southwest winds. Rain is expected below about 1200 metres.

The new snow has buried melt freeze crusts at lower elevations and on solar aspects and otherwise added to 30 to 50+ cm of settling dry snow from this week's storm. The new snow may be particularly reactive to triggers where it buries crust.

Cornices have also become very large along ridgelines and always have the possibility of failing naturally or from the weight of a human.

A weak layer of facets buried mid-February may now be found around 120 to 150 cm deep, or shallower in the east of the region and in thin snowpack areas. The most likely place to trigger this layer is where the snowpack is shallow in alpine terrain. Large loads, such a cornice falls or multiple sleds on the same slope often trigger slopes that a single rider couldn't trigger on their own.

• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Storm slab size and sensitivity to triggering will likely increase through the day.
• Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.