Avalanche Forecast

High -

THURSDAY NIGHT: Partly cloudy / Moderate, southeasterly winds / Alpine low 5 C / Freezing level 2200 m.FRIDAY: Mostly cloudy with sunny periods / Moderate, southeasterly winds / Alpine high 5 C / Freezing level 2200 m.SATURDAY: Snow/rain; 5-10 mm precipitation / Strong, southerly winds / Alpine high -1 C / Freezing level 1300 m.SUNDAY: Mix of sun and cloud / Light, southeasterly winds / Alpine high 0 C / Freezing level 1500 m.

Observations in the Skeena corridor and Shames area on Sunday through Wednesday have been showing evidence of the ongoing natural avalanche cycle affecting all aspects and elevations. Numerous natural loose wet avalanches continue to be observed, with some reaching size 3 (very large). Explosives control yielded slabs that initiated at the March 10 interface but gouged deeply into isothermal (slushy) and faceted (sugary) snow. Observations show the largest loose wet avalanches reaching the full extent of their respective avalanche paths.Initial reports of the avalanche cycle came from the Shames area on Sunday, with several very large (size 3) slab avalanches observed running full path with more numerous audible large avalanches. This initial activity was focused on steep, sun-exposed aspects. The March 10 interface has been the primary failure plane in slab releases.Avalanche activity has been similar if not more pronounced in the Bear Pass area and further north.Expect the heightened avalanche activity described above to continue while temperatures remain elevated and overnight cooling weak.

50-100 cm of settled snow forms the upper snowpack at higher elevations, the product of storms since the drought ended on March 10. At lower elevations this precipitation came as rain. With the help of warm temperatures, this recent snow has either settled into a slab on shaded aspects or become increasingly isothermal (slushy) on sun-exposed aspects. Where it exists as a slab, it covers a variety of old snow surfaces left in the wake of the drought. These include crusts on solar aspects, facets (sugary snow) on shaded aspects at higher elevations, and surface hoar (weak, feathery crystals) in shaded/sheltered locations. This variable layer has been the primary failure plane in recent slab avalanches.Not much further below this storm snow interface is a second weak layer buried on February 19, primarily made up of weak facets or surface hoar. Recent loose wet and slab avalanches have been observed gouging into this faceted snow and entraining additional mass.The lower snowpack is generally considered to be strong in most areas, except for rocky areas in the alpine with a shallow or highly variable snowpack depth.