Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain

Tuesday Night: 10-30cm of new snow(more in the south) / Strong to extreme southerly ridgetop winds / Freezing level around 1200m.Wednesday: 5-20 cm of new snow / Moderate southwesterly ridgetop winds / Freezing level around 1100m.Thursday: 5-10 cm of new snow / Moderate southwesterly ridgetop winds / Freezing level around 800m.Friday: Mostly cloudy with flurries; 3-5cm / Light southwesterly ridgetop winds / Freezing level around 800m.

An impressive natural storm slab avalanche cycle occurred in response to new snow and wind on Monday. In some of the big east-facing terrain to the west of the Upper Lillooet Valley, evidence of natural activity to size 4 was observed, while explosives control produced storm slabs in the size 1.5-3.5 range.Looking forward, forecast snow and wind will promote ongoing surface storm slab avalanche activity, while surprisingly deep releases within (or at the base of all of the recent storm) snow may be possible in isolated terrain.

The region has been pummeled by heavy snowfall and extreme southerly winds. By Tuesday morning the 72 hour snowfall totals were just over 100cm. Thanks to extreme southeast winds, I would anticipate extensive scouring and redistribution of the recent storm snow at all elevation bands with dense storm slabs lurking in lee and cross-loaded features. Impressive cornice growth is also expected to have occurred.About 150cm below the surface you'll find a crust that was buried mid-January and is present at all elevations. This crust is thin on northerly aspects and up to 3 cm thick on solar aspects. Most reports suggest an improving bond at this interface, but the load of the new snow may tip the balance and reactivate this layer in isolated terrain. Below this, the snowpack is generally strong and well-settled.