Avalanche danger could reach HIGH by the afternoon with sunshine and intense warming. Pay close attention to rising temperatures and the sun's intensity. Stick to simple, low-angle terrain and avoid overhead hazard, especially during the warmest part of the day.
Large cornices exist along ridgelines and require a wide berth from above and below. The likelihood of them becoming weak and failing is HIGH with warming and solar radiation. They have the potential to trigger slab avalanches on the slopes below.
Two layers of concern exist and have been reactive over the past couple of days. The upper layer is down 30-60 cm and has recently failed primarily on a sugary facet interface. The next layer is down 60-100 cm and consists of surface hoar, facets, and/or a melt-freeze crust. The layer has been most problematic around treeline elevations and in openings below treeline, but also reaches into the lower alpine.
Wet loose avalanches are likely as the sun comes out and freezing levels rise. Watch for signs of warming and snowpack instability such as rolling snowballs, moist snow, and natural avalanche activity.
THURSDAY NIGHT - Mainly clear / moderate to strong southwest wind / alpine low temperature near 0 / freezing level 2300 m
FRIDAY - Sunny / moderate to strong southwest wind / alpine high temperature near 3 / freezing level 2400 m
SATURDAY - Mainly sunny in the morning and increasing cloud in the afternoon / moderate to strong southwest wind / alpine high temperature near 2 / freezing level 2400 m, dropping to valley bottom overnight
SUNDAY - Mainly cloudy with flurries / moderate southwest wind / alpine high temperature near -6 / freezing level 1500 m
There were a few size 1 natural and human-triggered wet loose avalanches reported on solar aspects on Wednesday.
There were also reports of several size 2-2.5 natural wet loose avalanches in the neighbouring Waterton National Park region, and two size 2.5 natural persistent slab avalanches in the neighbouring Kananaskis Country region.
Sun and warm temperatures are our primary concern over the next few days.
Upper elevations are highly wind-affected and scouring down to rocks or crusts can be seen on west to southwest aspects. On leeward (northeast-east) slopes, stiff pockets of wind-slab have formed at treeline and in the alpine.
40-60 cm (in some places up to 100 cm) of snow sits above a persistent weak layer of facets that was buried in mid-February. Recent snowpack tests indicate that this layer is reactive and has the potential to propagate widely, causing large avalanches.
There is another persistent weak layer that was buried at the end of January. This layer consists of surface hoar, facets, and/or a hard melt-freeze crust. recent MIN reports show that these layers remain easily triggered by people.
Weak faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack.
