Paris Soir - Rock and ice prevent rescue work after Swiss glacier collapse

The Birch glacier in Switzerland's southern Valais (Wallis) region collapsed on Wednesday, sending a mass of rock, ice and scree hurtling down the mountain slope and into the valley below.

The barrage largely destroyed the most of Blatten, which had been home to 300 people and was evacuated last week due to the impending danger.

One 64-year-old man, believed to have been in the danger zone at the time, remains missing. A police spokesman said the difficult conditions had forced the search to be called off Thursday.

The unstable mountain face and thousands of tonnes of rocky debris also made it impossible for emergency workers to intervene to stabilise the zone and contain the risk of flooding in the valley below, officials told a news conference.

The huge pile of glacier debris, stretching some two kilometres (1.25 miles), has blocked the river Lonza.

After initially warning of a potentially devastating flood from water trapped above the debris, authorities said expert analysis indicated the risk had eased.

"The information we've received from geologists and other specialists tends to indicate such an event is unlikely," Valais security chief Stephane Ganzer told a news conference.

An artificial dam in the village of Ferden, just below, has been emptied and should be able to contain any downward rush of water if it happens, said Ganzer.

However, he added: "It's unlikely, but we don't really like that word 'unlikely' here since yesterday, because we know that unlikely can become likely."

- 'Terrible catastrophe' -

Authorities are studying evacuation plans and have warned residents who could be affected, Ganzer said.

"We have one person missing, we don't want anyone else missing or deceased from this terrible catastrophe," he said.

As a precaution, 16 more people were evacuated Wednesday from two villages located downstream from the disaster area in the Loetschental valley, known for scenic views and home to around 1,500 people living in villages.

Their views of the valley have definitively changed now.

Where the Birch glacier used to sit, there is now a gaping hole in the mountainside.

What is left of the village of Blatten is being submerged beneath the accumulating water of the Lonza river.

A sunny and warm weather forecast means "lots of snow" will melt in the coming days, meaning "we're still facing colossal water levels" in the artificial lake that has formed, Ganzer said.

- Seismic event -

YouTube footage of the collapse showed a huge cloud of ice and rubble hurtling down the mountainside, into the valley and partially up the mountain slope on the other side.

The force was such that Swiss monitoring stations registered the phenomenon as a seismic event.

According to officials, three million cubic metres of rock fell suddenly onto the glacier, pushing it down into the valley.

Warming temperatures have shrunk the Alps' glaciers and made them more unstable.

Swiss glaciers, severely impacted by climate change, melted as much in 2022 and 2023 as between 1960 and 1990, losing in total about 10 percent of their volume.

In August 2017, approximately 3.1 million cubic meters of rock fell from Pizzo Cengalo, a mountain in the Alps in Graubuenden canton, near the Italian border, killing eight hikers.

Some 500,000 cubic metres of rock and mud flowed as far as the town of Bondo, causing significant damage there but no casualties.

H.Robin--PS