Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches possible, human triggered probable.
Below Treeline
Natural avalanches unlikely, human triggered possible.
Alpine
Natural avalanches possible, human triggered probable.
Treeline
Natural avalanches unlikely, human triggered possible.
Below Treeline
Natural avalanches unlikely.
Regions
Little Yoho.
This is a good time to be conservative in your terrain choices and minimize exposure to avalanche terrain. The chances of human triggered avalanches will increase as temperatures rise.
Weather Forecast
A temperature inversion will continue through the forecast region, with alpine temperatures above freezing through Monday into Tuesday. Skies will remain relatively clear and winds light. Expect unusually strong solar outputs for this time of the year on South and West aspects Monday and Tuesday afternoon.
Snowpack Summary
Warm alpine temperatures have moisten the upper snowpack on steep solar aspects. There is 40-65 cm over the Dec.15 persistent weak layer of surface hoar at treeline. This is becoming reactive to skiers and producing easy to moderate test results as shown in this video from Mt Field. Below this is a faceted but generally supportive snow pack.
Avalanche Summary
Snowballing observed around rock features on steep solar aspects Sunday afternoon. No new avalanche activity observed. A field team Saturday traveling up Mt Field noticed lots of whumphing and cracking in open glades at treeline, this activity was failing on the Dec.15 persistent weak layer.
Confidence
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.