This is the river that flooded the road out between Cusco and Abancay. For a period of time the missionaries were trapped in Abancay and the only way out would be to go to Andahuaylas.
Notice that parts of the road is gone. A temporary road of gravel had to be built. Closer to Abancay part of the highway was missing only it was about 1,000 feet down. We couldn't stop to take a picture as there was no place to pull over and stop.