The cliff face of Lake Furnas in Brazil collapsed on Saturday, January 8, hitting four boats filled with tourists. Videos posted on social media show the moment the massive rock fragment fell.

Six people were initially reported dead, but that number has gone up to 10. Additionally, more than 30 people were injured, including some who had to be hospitalized. All victims were Brazilian and between 14 and 68 years old, according to CBS.

Lake Furnas was formed by a hydroelectric dam in 1958, and it’s since become a tourist destination due to its cliffs, caves, and waterfalls. Nearby Capitolio only has about 8,400 residents but draws some 5,000 tourists on weekends and 30,000 on holidays.

One woman who was there, Andréia Mendonça, reportedly told her boat captain that she noticed pebbles falling into the water, according to the New York Post. The cliff face collapsed shortly after. The boat Mendonça was on made it to safety.

Divers and helicopters from the local fire department assisted in the early rescue effort.

“We are suffering the pain of a tragedy in our state due to heavy rains, which caused the loosening of a wall of stones in Lake Furnas, in Capitolio,” the governor of Minas Gerais, Romeu Zema, posted on social media. “I stand in solidarity with the families at this difficult time.”

This rainy season has been particularly hard. More than 17,000 people have been forced to evacuate due to heavy rains over recent weeks, USA Today reports. The US Agency for International Development has sent more than $130 million in aid to people in the state of Bahia directly north of Minas Gerais.

Tiago Antonelli, head of the Applied Geology Division of the Brazilian Geological Service, told the Associated Press that natural causes caused the collapse.

“It’s normal to happen in many canyons, even with rocks of that size,” Antonelli said. “But nowadays, with the intensification of tourism, people are starting to get closer to these places and to register these phenomena with their cell phones.”

Reports note that falls from natural erosion are more likely in December and January, the region’s rainy months. Risk analysis studies weren’t conducted on the rock wall, but Capitolio Mayor Cristiano Geraldo da Silva told the press that it’s needed from now on.