Avalanche Forecast

The most likely early season problem you’ll have to deal with involves wind and storm slabs that are poorly bonded to the underlying snow. These are most dangerous during and immediately after a storm and are most commonly found in alpine bowls and in the lee of ridgelines. The danger can last much longer where slabs of this season’s snow overlie old patches of snow from last year, on sit on top of glacial ice. This is because the bond between last year’s snow and this year’s is often quite poor. Temperatures will typically fluctuate at this time of year, often bouncing above and below zero C. If you get a rapid spell of warming, or worse—rain, immediately after a good dump of snow, there’s a good chance of seeing an avalanche cycle. The consequences of being caught in an avalanche are heightened at this time of year, since trees, stumps and rocks litter runout zones. This is worth keeping in mind, as getting dragged through this kind of nastiness is definitely something to avoid.

At this time of year, successive early winter storms lead to a rapid buildup of the snowpack. Expect big changes to the snowpack structure with elevation, with full-on winter conditions in the Alpine and little or no coverage lower in the valleys. Here are some things to look for in the snowpack that might help you identify potential avalanche danger. First, the quality of the slab. If the upper slab feels dense and has a tendency to crack or pull apart as a cohesive element, there’s a good chance conditions are primed for a slab avalanche. Second, try to identify areas where you might be riding over old snow from last year. These pockets often exist near the top of bowls, on the shaded side of steep gullies and under cliffs. Basically, they favour steep, high elevation north facing terrain. These pockets cause problems because the new snow from this year often bonds poorly to the old snow surface. This is particularly a problem where the new snow falls on steep glacial ice. Third, if you identify crusts within the snowpack, these can act as sliding layers, as well as promoting the growth of sugary facets above or below.