Video images showed a gathering of small boats moving slowly near the sheer rock cliff on Furnas Lake, Brazil, when a fissure appeared in the rock and a huge piece toppled onto at least two of the vessels.
Edgard Estevo, commander of the Minas Gerais State Fire Department, said at a news conference that in addition to the dead as many as 20 people might be missing and officials were seeking to identify them after the accident Saturday.
Officials said at least 32 people were injured, though most had been released from hospitals by Saturday evening.
Furnas Lake, which was created in 1958 for the installation of a hydroelectric plant, is a popular tourist attraction.
Officials are guessing the wall coming loose could have been related to heavy rains recently that caused flooding in the state and forced almost 17,000 people out of their homes.
– Ella Breedlove