What can winter storms do

Winter storm

Winter storms in Switzerland

Winter storms hit Switzerland between October and April. They arise from the strong temperature and pressure differences that can prevail over Europe in connection with the shift of the polar front (border between tropical warm and polar cold air). Pronounced frontal zones can be recognized in weather maps by clustering of isobars (lines of equal pressure) in a narrow space.

 

The hurricane-like winds, which mainly come from the west, have a very large-area effect - the trajectory of winter storms can affect several hundred square kilometers, be up to 2000 km long and run over several countries. As a rule, they last from one to several days. They basically affect the whole of Switzerland, but the south and east somewhat less often than the northern and western parts of the country. The strong gusts that occur during winter storms are mainly responsible for their destructive effect: the briefly occurring strong gusts of wind can reach values ​​with top speeds of up to 250 km / h that are twice the mean wind speeds during a winter storm. With regard to the action of forces, a doubling of the wind speed means a quadrupling of the force.

 

No other form of storm in Switzerland causes such high sums of damage as a winter storm in the context of a single event. The strong winds kink branches of trees or uproot whole trees and damage parked vehicles as well as roofs and facades of buildings. In extreme cases, the gusts of wind can damage the load-bearing elements of buildings, causing them to collapse and completely destroy them. Interruptions in traffic routes and power supply are also frequent consequences of winter storms. Loose objects, whirled around by the wind, can also be dangerous to people who are outdoors.

 

Large-scale consequential damage from winter storms occurs above all when the windthrow affects large areas of forests with a protective function (protective forests). Individual buildings can also suffer major damage as a result of water ingress into the building through roofs that have been damaged by falling trees or by blowing away roof components.

 

The winter storms of 1990 (Vivian), 1999 (Lothar) and 2007 (Kyrill) also demonstrated in this country what great damage to property and, unfortunately, personal injury these natural events are capable of.