Sea To Sky

Wind slabs and cornices are the main concern for Wednesday. Forecast new snow and strong winds will likely add a storm slab problem by Thursday morning. Be alert to changing conditions and increased hazard.

Moderate - Timing of incoming weather systems is uncertain

Wednesday: 5-10 cm of new snow accompanied by strong southwest winds at ridgetop elevations. Freezing levels near 1500 m. Thursday: Another 10-15 cm expected overnight and tapering off throughout the day. Ridgetop winds light with strong gusts from the southwest. Freezing levels near 1400 m.Friday: A mix of sun and cloud as the arctic front shifts over the region. Alpine temperatures near -12 with a high of -4. Light-moderate ridgetop winds from the northeast and freezing levels near 900 m.

On Monday, cornice control done with the use of explosives triggered numerous cornices up to size 2.5, mostly just entraining snow mass from the slope below. The larger cornice failure (2.5) did pull a small slab avalanche on the slope below. Cornices and wind slab avalanches remain touchy to rider triggers.

We've had small amounts of new snow over the past several days. Winds, however, have been consistently strong from the south (east), forming reactive wind slabs in exposed downwind (lee) terrain. Snow surfaces vary with wind pressed, scoured or 10 cm of fresh, low density snow in the alpine. Treeline and below treeline a melt-freeze crust exists with moist snow below 1500 m. The new snow adds to the 170 cm of snow that fell during the last few weeks of January. These series of storms were accompanied by strong to extreme winds which resulted in extensive scouring and impressive cornice growth in upper elevation terrain. These accumulations sit on a crust from mid-January which generally shows signs of bonding to the overlying snow; however, it has the potential to "wake-up" with a large trigger such as a cornice fall.Below this, the snowpack is thought to be generally strong and well-settled.