Observation of an avalanche in Nufenen, Rheinwald
Considerations on images sent by a user, using the Observe & Report function of the Bluerando app
Let’s imagine that we are at the spot where the photo was taken.
We are at the beginning of the trip, we should not be particularly tired yet, so our observational capacities are still high.
However, in reality we are moving, so the images flow faster and change as we go along.
But let's try this game anyway.
How many cues come to mind as you look at the picture?
Try counting them; I would say a dozen.
Exposition SW
Altitude 1670 m
Air Temperature -11° C
The eye immediately falls on some wind and bottom slabs (1), detached naturally (no skier or animal tracks visible) at the points of change of slope; all more or less with the same exposure (SO as indicated by the photographer).
That these are wind slabs is clear from the presence of small frames (2) indicating wind action on previous days with direction from right to left in the photo (NE to SO).
The fact that there was fresh, light, and therefore wind-transportable snow in the previous days is also shown by the presence of some snow on the trees (3).
So snowfall with wind, light crystals, wind transport, warming enough to dislodge some downwind accumulation but not to completely melt the snow on the trees, probably due to a significant drop in temperature (at the time of the photo -11°C).
A proof of what has been hypothesised is also given by the presence of a few small avalanches with weak cohesion (point detachment) just below the rocks, which warm faster (4).
Higher in altitude, the same type of avalanches are observed, not bottom but surface ones (5). This must make us think that as we go up in altitude we will have to watch out for possible wind slabs that have not yet detached since the temperature will have been lower.
The presence of snow with cohesion, which is necessary for the detachment of slabs, is also proven by the shape of the track left by the skis (6). In the presence of snow with some cohesion, the edges of the track are sharp, while in the absence of cohesion the snow falls back toward the center of the track itself after our passage.
Wind action is also visible from typical marks on the surface of the snowpack (7). This is very important to observe because with low visibility these are the visible signs close to us, while frames may not be. And if we have wind here, most likely it will be stronger at higher altitudes.
The warming of the previous days can also be seen by observing the shape of the snowpack (8); looking carefully, we see that around us the snowpack has perfectly adapted to the ground surface, going along with every slight roughness, almost enveloping every relief. If during or immediately after a snowfall the temperature remains low, the surface of the snowpack is more regular, levelling and equalising the small curves of the ground.
Another important sign is the evidence that an avalanche can hit us even if we are skiing on a nearly flat road: we see this from photo (9). Here the visibility is perfect, the slope above the road very small, and consequently the size of the avalanche is also minimal; but it lets us imagine what can happen in conditions of poor visibility where we cannot see what we have above us (highlighting the importance of prior map reading).
Moreover, in front of us there are some other people (10) and the trail is already made; this should make us think about the fact that we will have other skiers above us. Let's keep this in mind if we will have to face narrow channels or steeper slopes that could also be traversed by someone going downhill while we are going up.
Finally as we look up we see clear skies and no wind or clouds (11), which gives us peace of mind about the weather development in the coming hours.
These are 11 cues; reflections that careful observation sends to our brain that we need to put in a corner and pull them out as we go along, adapting them to the new situation to anticipate and possibly correct our track and behaviour.
This is the exciting side of going to the mountains with our heads: being an active participant in every decision we have to make, reasoning, acting accordingly and never getting carried away like postal packages.
We will increase our knowledge, be better prepared and able to interpret the avalanche bulletin correctly, and ultimately we will have put together another piece for the benefit of our own and others' safety.
If you would like to see the observations that are the source for this article, click the links below:
Try the Bluerando app!
With Bluerando, you can save and share your snow activities with friends, check out reports sent by other users, and use the routes in the shared library.
Above all, you can share your location with your travel companions and record your Snow & Avalanche Observations and contribute to everyone's safety.
Ernesto Bassetti
Ernesto is one of the leading snow and avalanche experts in Italy and beyond.
By passion and by profession, he has been involved in mountain safety for over 40 years, with particular attention to the avalanche issue.
He is co-founder, and until 2020 Vice President, of MND Group; important international player in the field of mountain infrastructure and world leader in controlled avalanche release systems.
He is a ski instructor, National Ski Mountaineering Instructor, former director of the Mario Righini Ski Mountaineering School.
He was promoter, co-founder and soul of the "Servizio Valanghe Italiano" (Italian Avalanche Service), of which he held the Presidency for 18 years.
