I could die in the mud

Mudflows - dangerous mud

Danger at high speed

Danger from snow in winter and mudslides in summer: thousands of mudslides, known as mudslides, occur in the Alps every year. Most of the mudslides pose no danger, but mudslides repeatedly cause great damage and people keep dying.

In mudslides or mudslides, masses of water, mixed with sand, earth, rubble and wood, shoot into the valley. They bury houses, destroy roads and are at least as dangerous as snow avalanches.

Mudflows can travel at up to sixty kilometers per hour and usually occur in hilly terrain and in the mountains - all over the world. But mudslides are not everywhere due to the same cause.

The trigger in the Alpine region is usually water, for example during heavy rain or when the snow is melting. The water softens the soil and loosens it from the subsoil.

Slope debris - dangerous rubble

The slope debris is created above the vegetation zone, where trees no longer grow. If the slope is steep enough, the scree can loosen in heavy rain or snowmelt and descend into the valley. It hardly matters whether the mountain forest is healthy or not, as the mudslide is created independently of it.

The forest can only help in exceptional cases: If the mudslide has not yet picked up enough speed when it hits the mountain forest, the debris can get stuck between the trees and does not shoot down into the valley.

Talmure - danger from the river bed

Here, the mudflow occurs in a steep mountain stream, also during heavy rain or snowmelt. The bank edges break off and the mudslide takes rubble, mud and trees with it into the valley.

A healthy mountain forest could help here: The trees ensure that the water slowly seeps away and does not immediately flow into small streams. The roots also keep the soil stable so that it cannot slide off the bank edges so easily.

Mudslides in the Alps

In order for a mud to occur, it needs "material", that is, enough debris to break loose. In many parts of the world it can take time for enough debris to accumulate on a slope for a mudslide.

The advantage: once the debris flow has subsided, the area underneath is relatively safe for the near future. It takes time until enough material has been collected again.

In the Alps, on the other hand, due to the Ice Age and the glaciers, sufficient debris and debris has accumulated, and in theory there is almost everywhere enough material for a mudslide to descend.

But there is not enough water to transport the material. That is why mudslides in this country are always triggered by heavy precipitation or extreme snowmelt.

Because there is so much loose rock in the Alps, there is a high risk that another mudslide will come off after a mudflow.

More landslides due to climate change?

Climate change is likely to have an impact on the frequency of mudslides. It is assumed that there will be more thunderstorms with heavy rain in the future, which can then trigger mudslides.

However, there are no precise data on this yet. Predicting mudslides in the Alpine region is difficult overall. Depending on the area, different amounts of rain are required for a mudslide. That depends on the accumulated material and the nature of the soil.

Predict the danger

Science tries to predict debris flows. To this end, early warning systems are developed and hazard maps are created.

In the Swabian Alb, for example, researchers from the University of Bonn have inserted measuring devices into the ground that measure soil moisture and sound the alarm in good time before a mudslide emerges.