Fifteen climbers could still be missing, say authorities, after fall of ice, snow and rock on popular trail on Marmolada mountain in Dolomites.

The search for survivors of a glacier collapse in which at least six people have died has resumed in Italy’s Dolomites region.

Authorities believe as many as 15 people may still be missing after a large chunk of alpine glacier broke loose on Sunday afternoon and sent ice, snow and rock slamming into hikers on a popular trail on the Marmolada peak. Nine people were injured in the slide.

Emergency services spokeswoman Michela Canova told AFP the total number of climbers affected was unknown because the glacier fall hit an access path at a time when there were several roped parties there, some of whom were swept away.

She did not specify the nationalities of the victims, but Italian media reported that foreign nationals were among them.

In late evening, the National Alpine and Cave Rescue Corps tweeted a phone number to call for family or friends in case of “failure to return from possible excursions” to the glacier.

Rescuers were checking number plates in the car park as part of checks to determine how many people might be unaccounted for, a process that could take hours, said Walter Milan, a spokesman for the Corps.

Sunday’s search of the peak involved rescue dogs and at least five helicopters, but was paused on Sunday night amid fears that more of the glacier could come away.

The rescue corps had said the hikers were “hit by the detachment of the serac”, using a term for a pinnacle of a glacier. Two of the injured were in “grave” condition, it said.

Rescuer Luigi Felicetti told Italian state TV: “We saw dead [people] and enormous chunks of ice, rock.”

The SUEM (Servizio Urgenza Emergenza Medica) dispatch service, based in the nearby Veneto region, said 18 people who were above the area where the ice struck would be evacuated by the rescue corps.

The dispatch service said the avalanche consisted of a “pouring down of snow, ice and rock”.

Some of those trekking in the area where the avalanche barrelled through were tied together by rope, according to local emergency services.

Marmolada, which is about 3,300 metres (11,000ft) high, is the tallest peak in the eastern Dolomites.

“A breaking away of rock provoked the opening of a crevasse on the glacier, leaving about 15 people involved,” the emergency dispatchers tweeted.

The alpine rescue service said in a tweet that the segment broke off near Punta Rocca (Rock Point), “along the itinerary normally used to reach the peak”.

It was not immediately clear what caused the section of ice to break away but the intense heatwave that has gripped Italy since late June could be a factor, said Milan.

“The heat is unusual,” Milan said, noting that temperatures in recent days on the peak had topped 10C (50F). “That’s extreme heat” for the peak, he said. “Clearly it’s something abnormal.”

Experts at Italy’s state-run CNR research centre said the glacier would not exist any more in the next 25-30 years and much of its volume was already gone.

The injured were flown to several hospitals in the regions of Trentino-Alto Adige and Veneto, according to rescue services.

(Source: The Guardian)