Watch for changing conditions throughout the day as you move through elevation bands.
Rain at lower elevations increases potential for wet avalanche activity, while storm slabs may build at treeline and above.
Cornices may become weak with rain and rising temperatures. Cornice falls are hazardous on their own, and have the potential to trigger large avalanches on the slope below.
As rainfall and warm temperatures weaken the surface snow, wet avalanches become more likely. Avoid terrain features with wet and heavy surface snow.
SATURDAY NIGHT: Mostly cloudy. Freezing levels rise to 1800-2000 m overnight, with up to 10-20 cm expected above and rain below. Freezing levels around 1500 m. Moderate southerly winds.
SUNDAY: Mostly cloudy with 5-15 cm of snow. Freezing levels remain high, around 2000 m. Moderate to strong southwesterly winds.
MONDAY: Another 5-15 cm possible overnight. Clearing during the day with flurries delivering up to 5 cm, freezing levels remain around 1500-1800 m. Light northeast winds.
TUESDAY: Mostly clear with increasing cloud. Light southwesterly winds. Freezing levels reach 2500 m.
On Friday, isolated small wind slabs and cornice falls were reported at treeline and alpine elevations.
Warm temperatures, rain and sun on Tuesday, Wednesday and Thursday produced large wet avalanches on all aspects below the freezing line, and on steep sun affected slopes. Similar activity is expected with this approaching weather system. Human and naturally triggered cornice falls were also reported over the week. Cornices are expected to be weak and reactive to human triggers.
A large avalanche was reported on a steep alpine slope near Blackcomb on Thursday, likely failing on the mid February weak layer, now buried around 80 cm deep. While the trigger is unknown, it's likely that warming and strong sun had weakened the snowpack.
Mixed precipitation and snow will fall on a melt freeze crust that extends into the alpine on all aspects to 2000-2500 m and on south facing slopes to mountain top. On shaded aspects new snow will sit over wind affected surfaces. Lower elevations will likely see moist surfaces as rain breaks down the crust.
40 to 90 cm overlies the mid March interfaces. This layer exists as surface hoar in shady, wind-sheltered areas and a hard crust on sun-exposed slopes into the alpine. Several other weak layers exist in the upper and mid snowpack, reports suggest these layers are bonding well and avalanche activity is unlikely except from large loads like cornice falls.
