Human triggering of large persistent slab avalanches remains likely and could result in significant consequences.
The Moderate rating below treeline reflects the overhead exposure to persistent slab avalanches with the potential to run a long distance from treeline and alpine elevations.
The Icefields have received 100+ cm of recent snow, which has produced a large‑scale natural avalanche cycle. Any slope that has not released naturally should be regarded as highly susceptible to triggering; the consequences of which would be severe.
Avalanche control on March 25 produced mostly no results, with only a few small storm slabs triggered by large explosives at treeline and below. Field teams observed a limited number of natural persistent slab avalanches that occurred post-storm at treeline on east to south aspects, running large and wide. Avalanche control on March 21 produced persistent slab avalanches up to size 4, coinciding with a widespread very large natural avalanche cycle.
The Icefield's alpine has received 70- 120 cm of new snow since March 15th. Maligne has received 30-50 cm. A late March temperature and rain crust has formed below treeline and exists up to 2100 m. A persistent weak layer of facets and temperature crust is buried 70-170 cm. The midpack is generally well consolidated with facets near the ground. Average snow depths for the Icefields are 150-220 cm, and Maligne is 80-140 cm.
Friday
Mainly cloudy with scattered flurries.
Accumulation: 4 cm.
Alpine temperature: High -6 °C.
Ridge wind southwest: 20 km/h gusting to 60 km/h.
Freezing level at valley bottom.
SaturdayCloudy with sunny periods and isolated flurries.
Precipitation: Trace.
Alpine temperature: Low -10 °C, High -6 °C.
Mostly light ridge wind occasionally gusting to 50 km/h.
Freezing level at valley bottom.
SundayA mix of sun and cloud.
Precipitation: Nil.
Alpine temperature: Low -11 °C, High -7 °C.
Ridge wind southwest: 10-25 km/h.
Freezing level at valley bottom.
