Rome — Authorities said that a large chunk of an Alpine glacier slipped down a mountainside in Italy Sunday afternoon. It killed at least five hikers and injured eight others.

Italian RAI state TV reported that six fatalities had been recorded, but this number could not be confirmed immediately. It was not immediately known how many hikers may be missing.

Twitter account of the National Alpine and Cave Rescue Corps stated that rescue dogs and helicopters were used to search the area at Marmolada peak.

“There are five people who have been killed by the detachment to the serac,” the emergency services tweeted. This refers to a technical term that describes a pinnacle on a glacier. “There are eight people injured, with two in serious condition.”

The SUEM dispatch team, which is based near Veneto, stated that 18 people were in the area where the ice hit and would be evacuated by the Alpine Rescue Corps.

According to the dispatch service, an avalanche was a “pouring down snow, ice, and rock”.

Marmolada is an approximately 11,000 foot peak in eastern Dolomites.

“A breaking apart of rock caused the opening of the crevasse on glacier, leaving approximately 15 people involved,” emergency dispatchers tweeted.

In a tweet, the Alpine rescue service stated that the segment was broken near Punta Rocca (Rock Point), along the route normally used to reach the summit.

It was not immediately clear what caused the ice section to burst and rush down the slope of the peak. Walter Milan, spokesperson for the Alpine rescue service, said that it could have been caused by the intense heat wave in Italy since June.

Milan stated that the heat was unusual, noting temperatures at the peak in recent days had reached 10 C or 50 F. It’s clearly something unusual.

According to rescue services, the injured were flown by helicopter to hospitals in Trentino-Alto Adige or Veneto.