According to Brazilian fire service, a wall of rock toppled on motorboats below a waterfall in southeastern Brazil on Saturday, killing at least seven persons and badly injuring nine more.
At Capitolio, Minas Gerais, a tower of rocks abruptly broke free from the canyon wall and slammed into six recreational boats, causing a massive wave to break over the lake.
Videos posted on social media showed tourists shouting as the column of rock crashed into the water, smashing two boats.
Authorities said three people were still missing after others feared lost were located by telephone. Divers searched the lake.
The people hurt in the accident had broken bones and one was in serious condition in hospital with head and facial injuries. Some 23 others were treated for light injuries, he said.
The region has been under heavy rainfall for two weeks, which could have loosened the rock face.
On Saturday, a dike overflowed at an iron ore mine 300 kilometres to the east, cutting off a major federal highway.