Conditions are tricky right now. There has been a lot of wind, a persistent weak layer and now the sun is forecast to come out with warm afternoon temperatures.
Stick to low angle terrain on shaded aspects and look for areas without wind effect to find the best quality snow with the lowest avalanche risk.
10-30 cm of storm snow and strong to extreme S-SW winds have loaded lee areas at treeline and above with slabs up to 60 cm deep. The slab sits on a weak layer of facets, surface hoar or sun crust. Human triggering will remain likely in steep or wind loaded terrain for the next few days.
Clear skies and warm temperatures over the next few days may trigger a loose wet avalanche cycle in steep solar terrain. Smaller loose wet avalanches could trigger the persistent layers resulting in bigger slides. The amount of reactivity on this layer will depend on how sunny it is.
The recent storm has added load to an already shallow and weak snowpack. With this additional weight and warmer temperatures, there may be a reawakening of this problem in isolated areas. Areas of concern include thin, shallow, and rocky slopes.
On Thursday, helicopter avalanche control on Mt. Field, Stephen, and Dennis produced slab avalanches up to size 3. Any spot that looked like it could avalanche, did. Many avalanches triggered slabs from the side walls of the path.
On Wednesday, a skier triggered a size 1.5 avalanche in Lipalian 3, just outside the Lake Louise ski area boundary. One skier was carried 60 m but remained on the surface, uninjured. Sunshine patrol triggered a size 2 deep slab with explosives.
10 - 30cm of snow from last weekend has been blown by winds in alpine and treeline areas. This snow sits over a layer of weak facets, surface hoar or sun crust from the prolonged cold, dry period in February.
The mid-pack is generally facets, while depth hoar and crusts form an even weaker base. The snowpack is the weakest in eastern areas where snow depths are low. In these areas, the basal weaknesses should be carefully considered.
Warm, spring-like weather is here for the next few days. Expect sunny skies with good freezes in the morning and freezing levels rising to ~ 2300m in the afternoon. Ridgetop winds will be light to moderate from the west throughout the period. No precipitation is forecast.
