Flood risk threatens Swiss valley after glacier destroys village

ZURICH (Reuters) - A lake of water trapped behind a mass of glacial debris that buried a village and blocked a river in southern Switzerland this week has sparked fears of flooding in the Alpine valley, even as some water eased its way through the morass on Friday.

A deluge of millions of cubic meters of ice, mud and rock crashed down a mountain on Wednesday, engulfing the village of Blatten. The few houses that remained intact were later flooded.

The village's 300 residents had already been evacuated after part of the mountain behind the Birch Glacier began to crumble. Rescue teams were looking for a missing 64-year-old man but have suspended their search for now due to the difficult conditions.

Flooding increased on Thursday as the mound of debris almost 2 km (1.2 miles) across clogged the path of the River Lonza, causing a lake to form amid the wreckage, raising fears that the morass could dislodge and trigger more evacuations.

Late on Thursday, local authorities urged residents in Gampel and Steg, neighbouring and lower-lying villages several kilometres further downstream on the Lonza, to prepare for possible evacuation in case of emergency.

Still, by Friday afternoon some of the accumulated water had made its way through the debris and run off, indicating that it could be finding a way back to the river without raising the danger level, Swiss officials said.

Authorities are therefore sticking to safety measures put in place on Thursday and do not currently expect the situation to worsen, local official Christian Studer told a press conference.

The army has been standing by with water pumps, diggers and other heavy equipment to help relieve pressure on the Lonza, a tributary of the River Rhone, once conditions allow.

Residents have struggled to absorb the scale of destruction caused by the deluge, an event that scientists suspect is a dramatic example of the impact of climate change in the Alps.

The Swiss Insurance Association said the damage would likely amount to several hundred million Swiss francs, and that it was too early for a more precise estimate. How many houses were insured in Blatten was unclear, it said in a statement.

(Reporting by Dave Graham; Additional reporting by Oliver Hirt; Editing by Lincoln Feast and Gareth Jones)