… in the Northern French Alps and surrounding areas – worth noting, following and learning from.
“But”, you may say, “Every year there’s a weak layer – it’s always there”.
Yes, but every year ‘the weak layer’ is different. Plus, weak layers can evolve with new ones appearing in the snowpack at various times during the winter season. What’s different this year is that we have ‘persistent weak layer(s)’ with exceptionally unstable characteristics. Add in the lack of avalanche control and skier compaction, and one of the results is the type of tragic accident that we heard about in Courchevel a couple of days ago – see this article from the Dauphiné Liberé.
The current situation is a great learning opportunity for those of you not in the mountains. And for those lucky enough to be in the Alps, you can also apply this to help you have a fun, successful time and keep things acceptably safe. Below is an educational overview we put together on the current situation. If you frame the following information based on these three points below, it will help you to decide ‘Where you go… and why’. (If you have any questions or comments please leave them on the Facebook post or email us at email@example.com).
In our accident reduction ‘Safety is Freedom Framework’, the first three points under, ‘Where you go… and why’, revolve around decision making:
- Slope Angles of more or less than 30° (if you stay away from steep slopes of 30° or more, you are out of avalanche danger)
- The avalanche danger rating and bulletin
- Recent Avalanche Activity (what are the avalanches doing!?)
* For the first point above, Slope Angles of … 30° , here’s a link to a video that shows you a quick way of measuring roughly 30° without having to take your gloves off.
* On the second point, the avalanche danger rating in the Northern French Alps is currently 4 out of 5: a high risk. Risk 4 means that avalanche triggering is very likely, even by the load of just one skier, on many steep slopes over 30°. Triggering and exposure to avalanches is also possible on many lower angle slopes. Frequent medium or large sized natural avalanches (without human involvement) are also likely. See our definitions of what the different avalanche danger ratings mean.
* Finally on the third and perhaps most important decision making point on our list: Recent Avalanche Activity (images of activity on 07 01 2021 – before the current snowfalls ), ‘what are the avalanches doing?’ There are already numerous examples of recent accidental avalanche activity (remotely triggered and some very big).
Some other points to help you understand and decide…
This high avalanche danger level is due to:
a) A persistent weak layer in the snowpack.
This has been caused by this season’s relatively thin snowpack and a series of cold clear nights and days on and off since November. Learning more about this phenomena will help you understand why most avalanche accidents happen in December, January and February on North’ish facing slopes. You can find out more by seeing our on-line talks. For now, this video from ANENA (the French Avalanche Association) showing current snowpack observation on North’ish and shaded slopes is informative. (You may have to scroll down a bit as this is their FB page). They say that the situation is likely to evolve very unfavourably in the coming days on all slope orientations, especially on slopes that have not been skied or skied very little (i.e. little to no skier compaction).
See, also, our video below, which provides a quick view of what’s going under the snow that makes it unstable. We took this during one of our courses last week at 2300 m North facing in Tignes, Northen French Alps, after a stability test and before a probing and shovelling ‘companion rescue’ exercise. Sometimes just a quick fiddling around with the snow can be revealing!
Yesterday, in preparation for a ski-racing event, the Val d’Isère piste service tried to expose the very hard (highly prepared, packed and water-injected) world-cup piste they used in December. They found that this extremely hard layer had been sufficiently weakened to make it impossible for the race to go ahead – another indication of how weak the snowpack currently is.
b) High loading on top of this unstable snowpack.
This is compounded by even more loading from fresh snow which continues to fall. The snowfall started on Tuesday afternoon and still continues on and off. Amounts have varied from area to area. For example, the Haute Tarentaise (e.g. Val d’Isère and Tignes) received around 30 cm of fresh snow at 1800 m on Tuesday, 15 cm on Wednesday, 20 cm on Thursday and another 15 cm due Friday. Higher up the mountain, depths will be greater, with significant accumulations caused by the blustery NW winds. Add the load of a skier or skiers coming down (or up), and the result could be deadly!
c) High winds which have blown the snow around the mountain, often building it up into accumulations and densifying it (windslab).
d) Lack of skier compaction (we’re talking about thousands of skiers, not just a few), which normally has a stabilising effect.
e) Seriously reduced avalanche control by the authorities.
Saturday looks like it could be a beautiful sunny day in the mountains. It will be very tempting to go out ski touring in the fresh powder. We urge maximum caution !!!!
Safety is Freedom!
There’s a long list of evidence that shows how applying simple frameworks, checklists and memory aids reduce risk in ‘high consequence, low feedback’ risk contexts prevalent in: aviation, military, finance, health care, avalanche terrain etc.
See our HAT quick reference ‘Safety is Freedom Framework’ for accident reduction in avalanche terrain. The Framework is aimed at all levels of off-piste and touring: for beginners: a point of departure; for experts: a guide for further learning; for pros: it’s a great framework for client training and quick memory aid.
The Framework is best if accompanied by training such as HAT events and on-snow courses, but it’s also a useful companion for all training as it focuses on the basic key points that all avalanche training courses address – it helps you to keep focused on the essential accident reduction points.