You’ll see our ski resorts posting warnings of preventative avalanche exercises (or PIDA in French for short), particularly after a heavy snowfall. But what is a Prévisions de Déclenchement d’Avalanches and how does it affect your time on the pistes?
Usually after around 15cm of fresh snow has fallen, our ski lift operators will initiate a PIDA exercise to clear excessive snow and avalanche risk from the areas above pistes, roads, ski lifts or houses. In addition to the volume of snowfall, other factors such as wind direction, temperature and changes in the snow pack will determine the avalanche risk on the slopes. Explosives are used during these controlled avalanches, which usually take place in the early hours of the morning, when the mountains should be empty; you’ll hear the blasting rumble around the valley, it’s unmistakable.
The avalanche risk at any given time is of clear significance to those who like to journey off piste in our ski resorts. Skiers and snowboarders with a thirst for adventure should always be well-educated in the dangers, have the correct safety equipment and the knowledge of how to use it. However it’s important to understand that the objective of PIDA isn’t necessarily to secure off-piste areas. Controlled avalanche activity seeks to secure the pistes and lift networks.
Those managing our pistes and lift networks watch the weather forecast constantly. When a large volume of snow is on the horizon, they’ll make the decision to activate PIDA the following day, before publishing a notice to let resort residents and holiday makers know. Here’s an example of how Morzine’s lift operating company Domaine Skiable de Morzine communicate their PIDA announcements on their Facebook page.
With mountain sports such as ski touring and splitboarding becoming increasingly popular, this announcement serves as a notice to anyone considering an early morning tour into the mountains to stay safely in bed. For those of you who prefer to stick to the pistes, it’s reassuring to know that the piste and lift network has been secured overnight, ready for opening.
Ski resorts use a number of different methods to clear the pistes of avalanche danger. GAZEX pipes (visible as you approach the top of the Arare lift in Avoriaz 1800 for example) are typically used in hard-to-clear areas and can be remotely detonated throughout the night to keep snowplough drivers safe. CATEX cables are also used to discharge explosives at specific points, again remotely to preserve the safety of the PIDA team. At other times, hand grenades become the most precise way to clear a potential avalanche, however this method can only be undertaken in daylight. It’s for this reason that you might find the first lifts in your resort are temporarily closed when you arrive in the morning while the detonations take place and it goes without saying that you should never enter a closed piste. Pistes are always closed for a good reason!
Later this season the Piste X Code team will go behind the scenes, following the experts who work tirelessly to keep our pistes safe.