Weisshorn glacier alert raised after ice break-offs above Randa

Authorities in Valais have placed the Weisshorn East hanging glacier above Randa under Level 3 monitoring after its movement accelerated and sections of ice broke away.

At least three break-offs took place on Monday, 24 August, and the largest was recorded between 17:00 and 18:00. The ice fell onto the glacier plateau below the unstable section, according to the Municipality of Randa.

Further collapses could reach the established danger perimeter. Official walking and cycling routes within that area remain closed until further notice, and the municipality has told people to observe barriers and signs.

Randa village is not currently considered at risk. The road and railway through the Mattertal towards Täsch and Zermatt also remain open, with an early-warning system in place to stop traffic if necessary.

Radar tracks movement above the valley

The hanging glacier, at about 4,000 metres, had been under closer observation since the end of June following increased activity. Monitoring intervals were shortened on 24 August after a further rise in the speed of the unstable ice.

Movement within the ice mass is tracked by an interferometric radar installed specifically for that purpose. Because of poor weather, experts initially could not reliably estimate how much ice had already detached, while the likely scale of another collapse remains uncertain.

Speaking to Swiss broadcaster SRF, natural-hazard engineer Norbert Carlen said that “another collapse is expected”, but added that “it remains impossible to determine whether a small section or a much larger part of the glacier will detach”. Carlen described a worst-case scenario in which the volume breaking away could reach several hundred thousand m³.

An ice avalanche reaching Randa is not shown in current simulations. The glacier plateau beneath the unstable section would be the first area reached by any falling ice, and it is where the deposits from Monday’s break-offs came to rest.

Glaciologist Martin Funk said monitoring equipment had been operating in the area for more than ten years. If the system detects a sufficiently large collapse, “the road and railway can be automatically closed”, protecting the main access corridor used by visitors travelling towards Zermatt.

Cantonal authorities said the situation differs from the May 2025 collapse at Blatten, where around three million cubic metres of rock, ice, mud and water buried most of the village. The Weisshorn ice is higher above the valley and separated from Randa by the glacier plateau.

The incident is separate from the 5 August rockfall on the Matterhorn’s south face, which led guides to suspend Italian-side ascents. For Randa, restrictions remain confined to the marked danger perimeter while monitoring continues.