Question

Why can a heavy rain shower cause a large amount of erosion in a desert area

Answer 1

Roots of trees and vegetation hold the earth together and prevent it from eroding

in the desert, there aren't as many roots to keep the sand/soil from moving so when it rains, te soil is free to move, it moves much more than in a forest or on a mountain.

Answer 2

There is a lack of vegetation to hold the soil in place.