Danger is expected to increase over the day. Be ready to dial back your terrain selection if you notice signs of instability and treat danger as HIGH if you encounter more than 30 cm of new snow.
New snow and strong winds will be forming new wind slabs. As the rain line climbs, these will gradually become restricted to higher elevations. Rain on dry snow is an effective avalanche trigger.
Large avalanches could be triggered from thin spots or with a large trigger, like a cornice fall or a snowmobile trenching.
The rain line will climb over the day. Steep slopes at elevations receiving wet snowfall or especially rain on previously dry snow will become increasingly unstable.
On Friday, a few large storm slabs were triggered with explosives east of Kelowna.
On Thursday, explosives control east of Kelowna produced several large (size 2) persistent slabs, which failed on the January crust that is 30 to 100 cm deep. This is the only recent evidence of persistent slabs reacting to large triggers in the region.
15 to 25 cm of new snow should accumulate by end-of-day Monday, adding to 20 to 40 cm since March 7, which has been redistributed by strong southwest winds in open terrain. It overlies a crust below around 1800 m and hard, old snow above.
Within the top 100 cm of the snowpack, there are a few layers of surface hoar, facets, crusts, or a combination of the three. The late-January layer is only about 70 cm deep. Other than Thursday's explosives results east of Kelowna, these layers haven't produced avalanches.
The remainder of the snowpack is well settled and strong.
Sunday Night
Cloudy with flurries bringing about 15 cm of new snow. 30 to 50 km/h southwest ridgetop wind, increasing. Treeline temperature -7 °C.
Monday
Cloudy with increasingly wet flurries bringing up to 10 cm of snow, mainly in the alpine as rain climbs to about 1700 m. 50 to 70 km/h southwest ridgetop wind. Treeline temperature reaching 0 °C with freezing level climbing from 600 m to 1800 m.
Tuesday
Mostly cloudy with light rain, possible wet alpine flurries with minimal accumulation. 50 to 70 km/h southwest ridgetop wind, easing. Treeline temperature 5 °C with freezing level reaching 2700 m.
Wednesday
Mainly sunny. 1 to 2 mm of rain at treeline. 40 to 50 km/h southwest ridgetop wind, easing. Treeline temperature 5 °C with freezing level between 2300 m and 2700 m.
More details can be found in the Mountain Weather Forecast.
