The eruption claimed 1,000–1,500 fatalities, not counting any fatalities from earthquakes or flooding on the Río Tambo. In Arequipa, houses and the cathedral collapsed during mass after an earthquake on 27February, concomitant with the beginning of the second stage. Tsunamis were reported during the eruption as well. Flooding ensued when volcanic dams in the Río Tambo broke, and debris and lahars reached the Pacific Ocean 120–130 km () away. Occasionally the flows that reached the Pacific Ocean have been described as pyroclastic flows. Reportedly, fish were killed by the flood in the Pacific Ocean at the mouth of the river.