Regions
Northwest Inland.
Beware intense storms, especially the one forecast for Monday, which could combine heavy snow amounts with warming temperatures.
Confidence
Fair - Intensity of incoming weather systems is uncertain
Weather Forecast
Friday night: 2- 5 cm expected overnight.Saturday: 10-15 cm new snow expected with freezing levels around 600 m. Strong winds, 50-60 km/h from the SW.Sunday: Scattered showers in the morning. Freezing levels around 600 m. Winds 30-40 km/h from the NW.Monday: Heavy precipitation. Current models are showing 15-20 mm for Smithers with 80-100km/h winds and freezing levels rising to 1500 m.
Avalanche Summary
A possible recent release was reported with few details close to Smithers on Thursday pm or early Friday. On Tuesday a steep rocky NE facing feature at 1900m released naturally resulting in a size 3 avalanche. The possibility for large avalanches appears to be still there, and the chance of one is likely to increase with anticipated warming.
Snowpack Summary
10-20 cm new snow fell on Thursday, which rests on a mix of surface hoar, small grained facets and melt freeze crusts.Previous to Thursday's snow, it was starting to feel like spring in the NW. Valley temps have been creeping into the double digits during the day, and there are reports of the top 15 cm of the snowpack regularly becoming moist with daytime heating. Previous snow falling between March 27th and 30th (15-30 cm) fell on top of a haggard old surface composed of old wind slab, melt freeze crust, and faceted old snow. I suspect the ongoing melt freeze cycles have largely healed any instabilities associated with this interface.The early March layer can be found down 75 - 100cm and is composed of facets/surface hoar on shady aspects and facets/crust on southerly aspects. The early February crust/facet/surface hoar combo is down 150 - 200cm. While it's been mostly dormant, I would not rule out the possibility of it reawakening if we see prolonged warming and/or intense sunshine.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.