What is the snowpack?

It is composed by the set of snow fallen to the ground and the layers of ice formed over time. It is a real transformer: sometimes you may sink inside the snow till the waist, some others you just stand on the surface. Knowing the snowpack is important because it can help predict how the snow will behave under its own weight and identify possible dangers, such as avalanches.

The stability of the snowpack depends on several factors, including density, temperature and snow structure. For example, a fresh and compact snowpack is less stable than one that is old and compacted by wind. In addition to these factors, it is also important to consider weather conditions. For example, in strong winds or bad weather, the snowpack may be deformed and the snow may accumulate unevenly, creating hazards for hikers.

The most dangerous risk, avalanches.

Avalanches usually form because one or more layers of the snowpack are not well bonded. This phenomenon affects temperature, humidity, thermal gradient, etc. Sometimes even a slight stress is enough to generate an avalanche.

More generally, the risk factors of an avalanche are:

• very heavy snowfall in a short time;
• when the process of daytime warming and subsequent night refreezing does not take place, the snowpack becomes unstable;
• type of soil: on grassy or earthy slopes, in fact, snow has greater difficulty in clinging to the ground, which can generate a weak layer;
• slope of the terrain: a steep slope can cause an avalanche to form;
• wind: gusts of wind can deform the snowpack and cause an avalanche to form;

How can we try to prevent unpleasant situations?

Some advices before you go

• Consult the avalanche bulletin, issued every weekday in winter: you will find all the information on snowmaking, snow cover condition and degree of danger;
• carefully organize the excursion: studying the itinerary allows you to identify the safest route, even in case of heavy snow;
• seek confrontation directly to people who are experts in the area: avalanches normally occur in the same places;
• do not forget the essentials: to be able to intervene autonomously make sure you have with you a probe shovel, an artva and a backpack with airbags.

Some local advices

• A dense forest is safer than areas with fewer trees;
• map and compass in hand! They are excellent allies in order to not lose orientation;
• if you go off track it is safer to avoid the dips, bumps and crests
• keep your eyes open: observe the surrounding environment and also pay attention to settling noises (woom).
• Prefer travelling in a group rather than alone.

What is an avalanche bulletin and a danger scale?

The avalanche bulletin is a document that briefly describes the snow cover, the state of the snowpack and the danger of avalanches. For this information, it is used a scale of 5 levels called "degrees of danger”.

The danger scale describes the probability of avalanches in terms of release and the degree of danger, based on 4 factors:

• The consolidation of the snowpack
• The odds of detachment
• The causes of the detachment
• The size of the avalanches

THE SCALE

GRADE 1 - WEAK

Snowpack consolidation:in general it is good and the snow is stable, but there are very few or isolated dangerous sites.

Odds of detachment: is present on very few (i.e. isolated) extreme steep slopes (more than 40°) and in unfavourable conditions. The snow can withstand additional stresses.

GRADE 2 - MODERATE

Snowpack consolidation: moderate. Dangerous sites are localised and generally require significant loads to trigger avalanches; however, isolated conditions of weak consolidation cannot be excluded.

Odds of detachment:is present on a few localised steep slopes (more than 30°)* indicated in the bulletin. The snow can withstand additional stresses quite well.

GRADE 3 - MARKED

Snowpack consolidation: moderate on many slopes, weak on some localised slopes.

Odds of detachment: is present on many steep slopes (more than 30°)*. The snow has limited ability to withstand additional stresses and also tends to detach spontaneously.

GRADE 4 - STRONG

Snowpack consolidation:is weak on most slopes.

Odds of detachment: it is present on many steep slopes (more than 30°). The snow, therefore, tends not to bear additional stresses and spontaneous detachments increase.

GRADE 5 - VERY STRONG

Snowpack consolidation: the snowpack is generally weakly consolidated and unstable, even on moderately steep slopes.

Odds of detachment: it is present on most steep slopes (about two thirds of the slopes), extending to moderately steep slopes (less than 30°). The snow is not able to withstand any stress.

If the weather forecast and environmental conditions are adverse, we advise against hiking in the mountains. To experience an outing in serenity, it is essential to approach the mountain with respect, safety and caution.The only possible challenge is the one with yourself, because if you challenge the mountain, aim for a draw.

If you need more information on avalanches and their risks, we recommend you consult the in-depth document of AINEVA, the Interregional Association for the Coordination and Documentation of snow and avalanche problems in the Alps, at this link link.

We would like to thank Maurizio Bartoli, Kayland ambassador and Avalanche Forecaster, who helped us in the development of this article.