A mixture of water and a high solid content of 30-60 % form a mudslide.

Mudslides can, for example, result when driftwood jams in mountain torrents break. They are able to transport an enormous amount of debris and can, for example, carry along entire tree trunks and boulders of several cubic metres in size with them. Due to the high water content, they can reach a speed of several dozen km/h, which makes advance warning impossible and escape very difficult. Mudslides have an enormous destructive power. Therefore, people are at risk indoors and outdoors.

Heavy rain

Heavy rainfall can cause land to be inundated and water can enter into buildings. When heavy rain falls onto compacted or frozen ground, the surface drainage takes place via infiltration restriction. In the case of streets and squares, this infiltration restriction has been created artificially. Therefore, the cause for flooding is not the rise in the groundwater level nor an overflowing river or lake, but the precipitation which runs off the surface and accumulates (surface water).


Avalanches can occur in a dry form (powder snow avalanche) or wet form (wet snow avalanche).

Due to their high speed (powder snow avalanche) and their large mass (wet snow avalanche) they can develop enormous force.

Once triggered, it is virtually impossible to stop an avalanche until it reaches the bottom of the valley. Large avalanches can destroy forests and building structures within seconds. They present a risk to people outdoors, and also inside buildings.

Snow pressure

Heavy snowfall can deposit large loads on roofs. The size and shape of the snow load are influenced by the following factors: climate, topography, location and structure of the building, impact of wind, type of roof cladding and heat exchange on the roof surface.


Head office St. Gallen

Egli Engineering AG
Bogenstrasse 14, 9000 St.Gallen
T +41 (0)71 274 09 09
F +41 (0)71 274 09 08

Branch office Bern

Egli Engineering AG
Schwarztorstrasse 87, 3007 Bern
T +41 (0)31 381 52 90
F +41 (0)31 381 52 91

Contact point Leysin (VD)

Egli Engineering SA
Avenue du Censuy 5b, 1020 Renens
T +41 (0)24 545 12 00

Contact point Fribourg

Egli Engineering AG
Route de la Poudrière 41,
1700 Fribourg
T +41 (0)26 526 10 09

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