South Rockies

A natural avalanche cycle is underway. Travel in avalanche terrain is not recommended.

Moderate -

Wednesday night: Clear. Light east winds. Freezing levels remaining near 3100 metres.Thursday: Sunny. Light east winds. Alpine high temperatures around +7 with freezing levels to 3200 metres, remaining elevated overnight.Friday: Sunny with cloud increasing overnight. Light northeast winds. Alpine high temperatures around +7 with freezing levels easing from 3200 metres to 1900 metres by mid-morning on Saturday.Saturday: Cloudy with wet flurries bringing up to 8 cm of new snow to higher elevations, light rain below about 1500 metres. Light northwest winds. Alpine high temperatures around 0 with freezing levels to 1900 metres.

A report from Tuesday in the Elk Valley described numerous natural persistent slab releases reaching size 2 (large) on southeast aspects at around 2200 metres. Further to this activity, any sun-exposed snow became isothermal (slushy and cohesionless), and huge whumpfs that collapsed the basal snowpack were triggered during ski touring.A report from Sunday in the Window Mountain area described snowshoeing party choosing to turn back after avoiding a large loose wet avalanche that ran into below treeline terrain. This highlights the importance of considering overhead hazards being warmed by the sun and potentially inverted (warmer at higher elevations) temperatures.Given the above activity, loose wet avalanches remain a daily concern in steep, sun-exposed terrain (and in runout zones) while concern is increasing for deep basal snowpack weaknesses that have the potential to produce very large and destructive slab avalanches.

Upper snowpack: Getting warm and moist during the day, likely forming weak crusts overnight that deteriorate during the day. On sunny aspects the upper snowpack has become increasingly isothermal (slushy and cohesionless) with successive days of warming. On lee slopes there may be buried hard layers of wind effected snow (buried wind slabs).Mid pack: The mid-snowpack consists of sugary faceted grains (facets) and layers of harder wind effected snow. Recent loose wet avalanches have been entraining additional mass by gouging into this faceted snow. These facets have also acted as a failure plane in recent slab releases.Lower pack: The strength of the lower snowpack is increasingly in question in shallower areas where the February cold was able to penetrate and weaken basal layers. Warm temperatures are increasing the strain on basal weaknesses each day. Basal snowpack and ground are evident in the start zones and tracks of many recent avalanches.It's a good time to stand aside and let the mountains shed their coat. Stability will improve greatly when temperatures cool off.