Solid overnight cooling means that surface instabilities remain the primary concern in the Cariboos. This may change in the coming days.Check out the Forecasters' Blog for more details: http://www.avalanche.ca/blogs/2018-03-09-first-big-warm-up
Weather Forecast
Sunday: Mainly sunny. Light south winds. Freezing level rising to 1800 metres with alpine high temperatures of -2.Monday: Sunny. Light southeast winds. Freezing level rising to 2500 metres with alpine high temperatures around 0 to +1.Tuesday: A mix of sun and cloud, becoming cloudier. Light southeast winds, increasing over the day. Freezing level to 2500 metres with alpine high temperatures of +2.
Avalanche Summary
Reports from Friday included numerous observations of loose dry avalanches reaching size 2. These occurred in steeper terrain on all aspects. Numerous recent wind slab releases were also observed to have run naturally up to size 2.5 on steeper north aspects.Thursday's reports included one observation of an older size 2.5 natural wind slab release in the south of the region. This avalanche occurred on a 40 degree southwest slope in the alpine and had a depth of 60 cm.On Wednesday, a chunk of falling ice triggered a size 2.5 avalanche. On Tuesday, a few large cornice falls were reported, without releasing large avalanches on slopes below. Avalanche activity is expected to increase as we move into a period of intense sun and prolonged warming. Predictable loose wet avalanches from steep, sunny terrain should be easy to manage. A trickier problem will gradually emerge as warmth penetrates into the snowpack to tickle deeper persistent weak layers that have lately been dormant in the Cariboos. The next few days will be a time to avoid exposure to large sunny features and keep well away from corniced slopes.
Snowpack Summary
Thursday's storm brought 20-30 cm of new snow by Friday morning. This new snow overlies well-settled storm snow from regular snowfalls over the past couple of weeks. Although several layers of sun crust can be found within this storm snow on solar aspects, recent snowpack tests have not been producing concerning results in the upper snowpack. Persistent weak layers from early January and mid-December are still being reported by local operators. They are generally considered dormant, but could wake up with forecast warming, a surface avalanche stepping down, a cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. A weak layer of facets also lingers at the base of the snowpack.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.