ICE AND ROCK AVALANCHE, BIETSCHHORN / BLATTEN, VALAIS (2025)

The Bietschhorn relief was modeled in 1938/39 by Swiss cartographer Eduard Imhof (1895–1986) for the Swiss Alpine Club (SAC) pavilion at the 1939 National Exhibition in Zurich. Imhof was a professor at ETH Zurich, where he founded the Institute of Cartography.

SCALE AND MATERIAL

The relief is made on a scale of 1:2,000, is made of plaster, and shows the mountain and its surroundings with great accuracy. Only rock, scree, and glaciers are depicted in the modeled area (approx. 9.4 km² in nature), as the area lies above the tree line.

SIZE AND STRUCTURE

The model is composed of three blocks, has a base area of approx. 137 × 170 cm, and measures approx. 95 cm from the base to the summit.

PRODUCTION

Imhof used high-quality topographical data: survey data on a scale of 1:5,000, numerous aerial photographs, photogrammetric images, his own drawings, and geological maps. The relief was created using a wooden staircase model, which was cast in plaster and then finely modeled. Casts were made from this original mold.

USE AND RESTORATION

Four painted casts were created in addition to the unpainted original mold. Today, the copies can be found at the Institute of Cartography and Geoinformation at ETH Zurich, at the Cantonal School in Solothurn, and in the collections of the Natural History Museum in Winterthur and the Alpine Museum in Bern.

In November 2005, the relief was extensively restored at ETH Zurich: the three individual parts were joined together, damaged structures were repaired, and the original gouache colors were reconstructed. Since then, the restored model has been on display at the ETH Hönggerberg campus.

SPECIAL ACKNOWLEDGEMENT

We would like to express our sincere thanks to:

• the ALPS Swiss Alpine Museum, Bern for the loan of the exhibit free of charge.
• Prof. Dr. Lorenz Hurni, Professor of Cartography at the department of civil, environmental and geomatic engineering at ETH Zurich, for his assistance in marking the ‘mass movement trail’ and glacier levels, as well as for providing information for the creation of the relief and making the historical photo available.