Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain on Thursday

Generally light snowfall (5-10cm) is expected on Thursday. A dry ridge should develop on Friday bringing mainly clear skies while overcast conditions are forecast for Saturday. Ridgetop winds should be moderate from the southwest on Thursday and then become light for Friday and Saturday. Daytime freezing levels are forecast to hover between 1100 and 1200m for the forecast period.

In the north of the region near Stewart, a few persistent and deep persistent slab avalanches to size 2.5 were reported on Tuesday. The avalanches were triggered by solar radiation or by large cornices falls. One of the avalanches (which was triggered by a cornice fall) occurred on a northwest aspect at about 1400m and is thought to have failed on the March 3rd surface hoar. The slab was 50cm deep, 40m wide and 80m long. New wind slab activity is expected on Thursday in response to new snow and strong winds.

As of Wednesday morning, up to 5cm of new snow had fallen with moderate to strong southerly winds. At treeline and in the alpine small wind slabs are expected to have formed. These wind slabs overlie a variety of surfaces which include a hard crust on solar aspects above 1300, moist or refrozen snow on all aspects below 1300, and settled wind slabs in exposed high elevation terrain. A layer of surface hoar or melt-freeze crust buried on March 3 is down 50-80cm and has been on the radar of professionals in the mountains north of Stewart. A more widespread crust/facet layer buried in early February can now be found down over a metre. Both of these deeper layers have become less likely to trigger, but have the potential for large avalanches especially with a large trigger such as a cornice fall. I'd be increasingly cautious during periods of warming or solar radiation.