These images of floods in Lima, Peru show the power of fast-moving water. It becomes much more dangerous when the river is pushing huge piles of debris.

https://m.youtube.com/watch?v=iy6LHR4FdCA

These latest pix were taken in Peru in 2017.

I am just wrapping up a 16-month trip in S. America. We visited Peru and Chile. We were in Santiago during heavy rains and floods in April, 2016. We were astonished to discover that the street in front of our hotel, which was in the center of the downtown area, actually turned into a river. The water was 6-12 inches deep. But really, we were lucky. At the edges of actual riverbeds, the effects of the currents are very strong. Some parts of these cities can go underwater.

The basic problem is that the western side of the Andes mountains is very steep. So when these mtns get hit by torrential rain, huge volumes of water start gushing towards the ocean. Peru and Chile just do not have the resources to build engineered-water channels. So the results are chaos.

Pete

How about building restrictions within defined (100 year, 500 year, etc.) flood plains? I would think that would help to some degree. It is usually better to have parks or some sort of green space in flood channels than housing or development....

Those certainly are impressive flood waters.

https://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=3586

This is a comprehensive overview of the Peruvian flooding and damage, together with a comprehensive discussion of the weather phenomena involved. Although Peru is far away in the Southern hemisphere, they are liked to us, especially in southern California, through El Nino....