Rescuers warned Monday about the waning hope of finding survivors after an avalanche that was triggered by the melting of an Italian glacier in a heat wave claimed at least seven lives.

Authorities claimed they didn’t know how many climbers were killed when the glacier collapsed on Sunday on Marmolada (the highest mountain in the Italian Dolomites). According to Maurizio Fugatti, chief of Trento province, the collapse caused ice-rock to rush down the slope at 185 mph.

Rescuers equipped with thermal drones searched Monday for heat from ice-trapped survivors. However, there are very few survivors left now because it has been too long since the fatal avalanche. Giorgio Gajer, head of regional Alpine Rescue Service, stated that this is due to the fact that too much time has passed since then.

Gino Comelli, a rescuer, spoke to the outlet after six bodies were recovered from the mountain. He said that the tragedy had caused the bodies to be “torn apart”.

As search and rescue teams continued to march at Marmolada, Monday saw an increase in the death toll. According to AGI, seven deaths were confirmed by Fugatti in the afternoon. Eight others sustained injuries, and 14 more remain missing. Two of the injured hikers were found in critical condition and three of them could not be identified immediately. As missing persons reports continued to flood in, it was not clear how many people were captured in the avalanche.

One day after a record high temperature of 50 degrees Fahrenheit was set at the summit glacier, the largest in the Italian Alps, the disaster struck.

Experts said that the global warming had caused the glacier to weaken over decades.

Michela Canova, spokeswoman for Alpine Rescue, said that an “avalanche” of snow, ice, and rock hit an access path when several roped parties were present. “Some of them were swept away.”

Trento’s spokesperson said that people are still being reported missing.

Corriere della Sera cited Trento’s chief prosecutor Sandro Raimondi as saying that he was afraid the death toll could double, if not triple, based on the number cars left in a nearby parking lot.

Canova cautioned against overestimating the number of climbers involved, saying that it was not yet known. Eight people were reportedly injured and had been rescued at the time.

Bodies taken from the ice and rock were brought to Canazei by the Italian Prime Minister Mario Draghi to discuss the avalanche. As night fell, helicopters and sniffer dogs were summoned amid concerns that the glacier might still be unstable.

Giovanni Bernard, Canazei mayor, said to AFP that rescuers are often in a difficult situation.

Images of an avalanche shot from a refuge near by show rock and snow falling down the mountain’s slopes.

Stefano Dal Moro, an Italian engineer, said to Corriere della Sera that it was a miracle they are alive while he was hiking with his Israeli companion. “There was a dull sound, then the sea of ice came up. It is useless to run. You can only pray it doesn’t come to you. As the ice melted, we sat down together and hugged our fellows tightly.

Massimo Frezzotti is a scientist professor at Roma Tre University. He told AFP that the collapse was caused in part by unusually warm weather, which is linked to global warming. Precipitation fell 40-50% during a dry season.

He stated that the current conditions of glacier correspond to mid August, not early July.

Renato Colucci, a glacier specialist, told AGI that the phenomenon was “boundless to repeat itself” because “for weeks temperatures at altitudes in the Alps were well above normal values.”

He explained that recent warm temperatures had caused a lot of water to melt glacier, which accumulated at the bottom and caused the block of ice to collapse.

Trento’s public prosecutor has opened an investigation into the circumstances of the tragedy.

According to the IPCC, glaciers in Scandinavia and central Europe could lose 60-80% of their mass by 2050.