Edgard Estevo, commander of the Minas Gerais State Fire Department, said the accident occurred Saturday in Furnas Lake, between the towns of Sao Jose da Barra and Capitolio. The local fire department deployed divers and helicopters in a frantic effort to rescue the stunned tourists from the lake.
Police Chief Marcos Pimenta said an unknown number of people were missing.
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"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," Minas Gerais Gov. Romeu Zema said on social media. "I stand in solidarity with the families at this difficult time."
Zema promised to provide "the necessary support" to families of the victims.
Brazil's Jornal O Globo reported that at least seven of the dead were on a speedboat called "Jesus."
Rocha desaba sobre banhistas em #EscarpasdoLago (MG)
Confira: https://t.co/xPnulAgs0E #R7Minas pic.twitter.com/zZukQA1cww
— Record TV Minas (@recordtvminas) January 8, 2022
The Brazilian navy was aiding the rescue and said it would investigate the accident. Video from the scene showed several small boats in a lake when a massive slab of rock tears away from the face of the cliff and slams onto at least one of the boats.
Heavy rains in recent weeks have overwhelmed the region, driving more than 17,000 people from their homes. Just two days ago, the Brazilian government issued a statement expressing gratitude to the U.S. Agency for International Development for providing funds for cleaning, hygiene and kitchen kits for those displaced by the flooding in the neighboring state of Bahia.
The head of the Applied Geology Division of the Brazilian Geological Service, Tiago Antonelli, said the cliff wall is subject to centuries of erosion and susceptible to rain, heat and cold.
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“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."
Capitolio is about 180 miles west of the state capital of Belo Horizonte, a city of 2.7 million people.
Furnas Lake was created in 1958 as part of a hydroelectric plant. It's a popular tourist area, and Capitolio, which has about 8,400 residents, can draw 5,000 visitors on a normal weekend and up to 30,000 on holidays.
Contributing: The Associated Press
This article originally appeared on USA TODAY: Brazil rock collapse leaves 10 dead after cliff crashes onto boats