Fresh snow and risk of avalanches, here are the signs to pay attention to

When doing activities in the mountains on fresh snow, with skis or snowshoes, there are some danger signs that should not be underestimated, starting with the inclination of the slope and the sinking test in the snow.Without forgetting the characteristic 'vuum' sound

BOLOGNA – The Alps are white again and among enthusiasts the desire to do activities in fresh snow explodes.But in the days immediately following heavy snowfalls it is necessary to pay the utmost attention in carefully evaluating the snow, its evolution according to the weather and the terrain on which you want to carry out the excursion, both in the planning phase and during the execution of the excursion. exit.Although we know that we cannot be exhaustive, the Italian Alpine Guides invite you to consult the avalanche bulletins issued by the forecasters and highlighted below some warning signs to keep in mind, with some food for thought, as well as a small test, to help face the snow with greater awareness and healthy curiosity.

SLAB AVALANCHES

Slab avalanches are among the most dangerous, statistically they are responsible for over 90% of avalanche victims.They happen when a compact layer of snow (the “slab”) collapses on top of a weaker layer and slides downstream.The initial fracture, which can be spontaneous or caused, often even by the passage of a single person, spreads quickly causing the detachment of the entire slab with even a very large front.

THE INCLINATION OF THE SLOPE

“The classic factors to consider for risk mitigation in the mountains – explains Davide Spini, Alpine Guide Instructor – are the snow and weather conditions, the terrain and the human factor.Of these three, the terrain is certainly the least "indecipherable" and the most reliable to evaluate in case of uncertainty or high danger.On the contrary, snow and people are sometimes variable, in time, space... and mood".

“Slab avalanches generally occur on inclinations from 30 to 45 degrees  – continues Spini – and the inclination of the slope is certainly one of the triggering factors of an avalanche, but fortunately it is also the easiest to quantify. Anyone who goes into fresh snow (on skis, snowshoes, or otherwise) must therefore be able to evaluate this fundamental factor, both in the planning phase and then on the individual slope.It is therefore important to make this assessment as you plan, or dream, your exit.Technology helps us in this:for some years, there have been applications that allow us to evaluate, with reasonable reliability, the inclination of slopes already in the planning phase.On the ground, estimating the slope is not easy, because sometimes perspectives are deceiving, but with a little practice and guided exercises you can learn to distinguish what can be potentially dangerous from what isn't."

“Among others, the “Fat Map” application (also available offline and in this case for a fee) can be very useful for this purpose, which helps both in the planning phase, thanks to the layer with the slope inclination classes , both on the ground, thanks to the 3D vision of the environment and the geo-localization function.Once the route has been planned with these tools, together with the snow-meteorological information, we will re-evaluate the risk directly on the ground to understand whether the slope is acceptable to climb or not, trying to balance the stability of the snowpack with the inclination of the slope and the consequences of a possible avalanche".

DANGER SIGNS

It is important to be able to detect signs of instability when we are in the environment:with a little training we can, in fact, obtain extremely important information with which to verify and integrate that present in the avalanche bulletin.“First you simply need to look around and observe the presence of any recent detachments:nature sometimes clearly warns us of possible dangers – explains Spini -.It is a clear signal that even a beginner with little qualified training can grasp, yet it sometimes seems to be "underestimated" even by experts.It is also important to realize that bad visibility does not allow you to observe this, and other, important danger signs.When visibility is not good, you need to be even more careful, stay away from steep slopes and prefer simpler hikes, possibly inside the woods, keeping in mind that the arrival of help will be decidedly slower and more difficult.In these conditions even a small injury can turn into a long, cold Odyssey."
Another important sign of instability is the so-called “Vuum” (also called “wumpf” or “whoom") The settling noise.When you hear this sound while traveling down a slope, even if it is slightly inclined, it means that the slab has collapsed the weak layer underneath; the noise is produced by the escape of air.“Basically we caused an avalanche – warns Davide Spini – if there is no sliding, perhaps it is only because at that point the inclination is less than 30°. The vuum is felt by those who open the track.Who is behind, though try to evaluate the snow cover, can possibly move from the track by a few meters (if we are not on a critical slope) e listen to what happens when the ski sinks:if the ski sinks little and gradually "rests" on something more and more compact, in general it is a good sign.If, however, when weight is given to the ski, this it sinks as if there were a void underneath, it's a negative signal."

FRAMES

The frames are overhanging structures which are formed by the action of the wind on the mountain crests.Heavy snowfalls, accompanied by wind action, lead to the formation of large cornices that are particularly unstable because they are made up of, and loaded with, soft and loose snow.“They form on the leeward side of a ridge, and are difficult to see or guess,  for those who climb the mountain from the windward slopes, the “eroded” ones, from which the wind blows – explains Spini –.They are also an objective danger: we must avoid passing under it or, if we are obliged to do so, limit the exposure time and the number of people exposed, in particular if the temperatures are mild like those expected for the current week because they facilitate detachment, even spontaneously.If we are on the ridge and there are cornices, in general the indication is stay away from their ends;the presence of rocks helps us understand the "solid" limits of a ridge.We also keep in mind that the collapse of a cornice, such as that of a serac, in unstable conditions, could cause the triggering of an avalanche; it is no coincidence that, in certain conditions, the cutting of a cornice is also used as a safety test. stability".

SNOW COVER TEST

There are different techniques for testing the stability of a snow cover, but a very quick and quite useful test to try to understand what snow cover we have under our feet is the stick test.“It is not a very accurate test – explains Alpine guide Davide Spini – but it is probably the most used in sports, it works quite well and can be done several times on the route because it is very fast.You need to push the stick (on the handle side) deep into the snow cover:if the first layers are soft and the base is compact and dense it is a good sign. If, however, when pushing the stick, I notice that it slows down, becomes hard and then I perceive "emptiness", it is a danger sign:there could be conditions for a slab avalanche.”

The Alpine Guides teach how to plan and lead an excursion in a snowy environment, analyzing the snow-meteorological variables, the terrain and the human factor in the different phases.In the field, in particular, they explain how to analyze the snow cover, how to grasp the danger signs and how to evaluate and mitigate the risk of being overwhelmed by an avalanche.The guided learning of this knowledge, together with the reading and management of the terrain, as well as the movement of the group, allows you to acquire valuable skills to learn to move independently in fresh snow.