The deadliest avalanche or glacier-related disaster in recorded history, killing up to 30,000 people when a seismically triggered debris avalanche destroyed Yungay, Peru.
Key Facts
- Death toll
- Up to 30,000 people
- Date
- May 31, 1970
- Trigger event
- Ancash earthquake
- Villages destroyed
- Yungay plus 10 nearby villages
- Flow distance to ocean
- 160 km
- Disaster ranking
- Deadliest avalanche/glacier disaster in history
By the Numbers
Location
Cause → Event → Consequence
The north peak of Huascarán had been considered unstable since a 1962 collapse. On May 31, 1970, the Ancash earthquake destabilized a glacier and large snowmass on this peak. The earthquake struck on a Sunday, when thousands of additional people had gathered in Yungay for market, greatly increasing the eventual death toll.
The dislodged glacier and snowmass surged rapidly downhill, accumulating loose dirt, rock, and water to become a massive mudflow. Despite Yungay lying outside the direct avalanche path, the slide overwhelmed natural geographic barriers and leveled the town entirely, also destroying 10 nearby villages before flowing into the Río Santa and traveling 160 km to the Pacific Ocean.
Up to 30,000 people perished, making it the deadliest glacier-related disaster in history. The Peruvian government prohibited redevelopment of the original town site and established a memorial there. Survivors resisted relocation, eventually forming present-day Yungay just north of the ruins, while the ruined cathedral and cemetery remain as visible remnants of the destroyed town.