By Henry's Avalanche Talk. Wayne Watson photoread more
Off Piste Snow Conditions
We're due for more fresh snow and wind over the next few days. The wind has been playing a massive part, hardening and compacting the snow, blowing it around the mountain, leaving some areas bare and others with deep snowdrifts and snow accumulation. The surface snow is often wind hardened. It is compact in places, but is lovely and light in others. When the sun comes out it will humidify the surface snow, particularly on south-ish facing slopes, which will then be crusty first thing in the morning after overnight refreezing, then softening as the day warms up.
With the heavy snowfall and strong winds, particularly on Saturday, a lot of windslab will be forming (especially at 'altitude' - 2400 m and up) along with areas of deep snow accumulation. The windslab will often contain 'graupel' (tiny rounded snowball like snowflakes that fall direct from the sky and form tiny weak layers once buried) very easily leading to collapse - especially with the rapid increase from the weight of a skier - and a slab avalanche. The weight of a single skier passing by could be enough to trigger (maybe even distance trigger) this brittle windslab near the surface of the snowpack. We need to be very aware, also, of the danger of triggering areas where deep wind-transported snow has accumulated, especially in leeward areas near ridges and passes.
The avalanche risk will probably rise to 4 with each substantial amount of snowfall. See our HAT advice for what all the danger ratings mean: http://www.henrysavalanchetalk.com/avalanche-forecasts-danger-rating. With all the fresh snow expected, we could see quite a few naturally releasing avalanches in the form of powder snow or windslab. Some of these could be quite large. If it rains at lower altitudes, there could also be some slides of heavy snow on steep enough slopes.
Tips of the Week
Like last week, the weather and snow situation will be very changeable and hard to predict this week. Keep checking our facebook page for updates: www.facebook.com/HenrysAvalancheTalkCheck the daily avalanche bulletins on this link: http://www.meteofrance.com/previsions-meteo-montagne/bulletin-avalanches, by clicking on the mountain area you're in.
Watch our new on-line 'Off-piste Essentials' talk: vimeo.com/ondemand/henrysavalanchetalk