Avalanche Forecast

High -

THURSDAY NIGHT - Cloudy with clear periods and isolated flurries / southwest winds 15-30 km/h / alpine low temperature near -14FRIDAY - Cloudy with scattered flurries, up to 10 cm / southwest winds 20-30 km/h / alpine high temperature near -12SATURDAY - Mainly cloudy with isolated flurries / northeast winds 10-15 km/h / alpine high temperature near -12SUNDAY - A mix of sun and cloud / northeast winds, 10-15 km/h / alpine high temperature near -14

On Wednesday, there were numerous reports of human triggered avalanches up to size 2, primarily on east and southeast aspects at all elevations. Four of these were persistent slab avalanches that were triggered remotely (from a distance) by people. They were on east aspects below treeline and failed on a persistent weak layer that was buried mid January. This layer is discussed in more detail in the Snowpack Summary below.Over the past week there have been daily reports of avalanches being triggered by humans, explosives, and naturally. Many of these are wind slabs in the size 1-2 range, but some of them are also persistent slab avalanches in the size 2-3 range. Persistent slab avalanche activity on the mid January weak layer has slowed down to some degree but it has not stopped, and they continue to be triggered by humans on a somewhat regular basis. Avalanches on this layer are becoming fewer and further between, but they tend to be large, potentially high consequence events.

Up to 10 cm of new snow is expected to fall on Friday with moderate southwest winds, which will likely form wind slabs in lee terrain. This new snow will fall on older wind slabs which may exist on all aspects due to previous variable wind directions. These older wind slabs will become more difficult to detect as they get buried.The new snow will bring recent snow amounts to 20-60 cm which overlies a weak layer of surface hoar (feathery crystals) and crust that was buried in early February. As this layer receives more snow on top of it, it may develop into a problem layer.Two additional weak layers of surface hoar have produced large avalanches in the region over the past month. A layer buried at the end of January is around 40 cm deep and a layer buried mid-January is between 50 and 90 cm deep. The mid-January layer may also be associated with a crust on southerly aspects. These layers are most prominent at treeline and below. The remainder of the snowpack is considered generally strong. However, there have been sporadic reports of very large avalanches that have released near the base of the snowpack. Most of these avalanches have been in the high alpine.