The mountain barred the river: this city found itself under a lake

In the spring of 1983, after heavy rainfall and the melting of a thick snowpack, an ancient landslide began to move again near Thistle, Utah. The mass progresses towards the Spanish Fork River. In a few days, it blocks the course and transforms the valley into a reservoir.

The lake that forms behind this natural dam floods Thistle. Roads and railways were interrupted. The Utah Geological Survey indicates that the water reaches a maximum depth of about 49 meters before being evacuated by diversion works. A railway tunnel then makes it possible to bypass the sliding zone.

The obstruction of a river had produced a lake instead of buildings. The mountain had changed the drainage of the valley; the infrastructure had to change places.