Avalanche Forecast

High -

Monday: Cloudy with sunny periods. Winds light from the southwest. Freezing level to 300 metres with alpine temperatures of -11. Tuesday: Mainly cloudy with flurries bringing up to 10 cm of new snow, beginning in the afternoon. Winds beginning light to moderate from the southwest, increasing to strong over the day. Freezing level to 700 metres with alpine temperatures of -7 Wednesday: Mainly cloudy with scattered flurries bringing 5-10 cm of new snow, beginning in the afternoon. Winds moderate to strong from the southwest. Freezing level around 600 metres with alpine temperatures of -9.

Reports from Saturday include observations of several skier triggered Size 1-2 wind slab avalanches occurring in the Spearhead Range. These have generally been described occurring in the immediate lee of ridge features where recent southwesterly winds promoted new slab development. One observation of a Size 1 wind slab stands out for its mention of a remote trigger (10 metres away) and a 40 cm crown fracture. It should be noted that aggressive terrain selection in the Spearhead Range may have been a contributing factor to a few more recent avalanche observations. Aside from above mentioned events, reports of both natural and skier triggered wind slab avalanche activity in the region have generally tapered off, with small natural and skier triggered loose snow releases from steep terrain dominating reports from the end of the week. A few small 10 cm slabs (under Size 1) reacted to ski cutting in the Spearhead Range on Friday.

Flurries over the past couple of days have deposited 1-5 cm of new snow on the surface. Strong northwesterly winds on Sunday morning have redistributed this and other loose snow at the surface, likely forming a few thin new wind slabs in lee terrain. Below any new snow accumulations, recent cool temperatures formed up to 5 mm surface hoar on the previous snow surface. The same low temperatures have been responsible for faceting at the snow surface and in the upper snowpack. Sun crusts exist beneath the skiff of new snow on steep solar aspects below about 1700 metres, with a more widespread temperature crust found below about 1500 metres. Below the new snow interface, roughly 20-40 cm of recent (faceting) storm snow appears to be bonding well the widespread mid-February melt-freeze crust. This crust extends as high as 2200 m and is up to 15 cm thick at treeline. Below this crust the mid and lower snowpack are well settled and bonded.