Heavy overnight snowfall and strong wind may quickly produce reactive slabs. Give new snow time to settle and bond.
Storm slabs will develop overnight Thursday with heavy snowfall forecast along with strong southwest wind. Expect to find a reactive storm slab as you gain elevation and snowfall accumulation, especially in areas exposed to the wind.
Rain on snow will quickly create a wet avalanche problem at lower elevations.
No new avalanches have been reported in the region.
Alpine observations are lacking, however, with precipitation falling as snow, higher elevations likely experienced some degree of natural avalanche cycle during this latest storm pulse.
30-60 mm precipitation is forecast within 24 hours through Friday. Snow will fall at upper elevations with the rain-snow line around 1200 m.
The new snow overlies moist snow above 1300 m and a new breakable crust below this elevation, a result of rain-then-snow over the course of the storm. This rain saturated as much as 70 cm that accumulated above 700 m from the previous storm pulse at the end of last week.
The new snow overlies a crust and temperature-affected snow above 1300 m and a new breakable crust below. This rain crust resulted from the snowpack saturated as much as 70 cm that accumulated above 700 m from the previous storm pulse at the end of last week.
These upper snowpack characteristics top a melt-freeze crust that is now likely breaking down where it was thinnest. The crust was previously up to 10 cm thick at lower elevations and tapered to 1 cm thick on shaded or high-elevation terrain. A few cm of softer snow recently found immediately below this crust is almost certainly now settled and bonded along with the remainder of the snowpack beneath it.
Thursday night
Heavy snow into Friday above 1100 m, rain-snow mix below, 15-30 mm. Strong to extreme southwest winds. Treeline low temperature -2 C with freezing levels dropping below 1000 m.
Friday
Snow and rain tapering around noon, 20-50 mm precipitation forecast within 24 hours. Rain-snow line around 1100 m. Strong south winds easing to light northeast. Treeline high temperature -2 C.
SaturdayScattered flurries and sunny breaks, up to 5 cm. Moderate southwest winds. Treeline high temperature +2 C.
SundayIncoming snow and flurries, 5-15 mm. Increasingly gusty and strong southwest winds. Treeline high temperature +2 C..
More details can be found in the Mountain Weather Forecast.
