I think if you pay any attention to droughts you realize most of the ground cover is reduced to tinder. When a large rain comes there is little plant life to slow water flow and erosion.
Several years ago I traveled to California by plane. As I flew over the hills and all land except commercial was a dead brown. Dead undergrowth, dead trees dead grasses. Not some but all a dead brown for miles upon miles. It was shocking and answered the question of how can thousands of acres burn so quickly and completely.
The result? Water runoff causing huge mudslides when it eventually did rain. I was there for 3 weeks and it didn’t rain once, not even a sprinkle. My travel companion at the time laughed when I turned on the Weather Channel in Southern California. Same temp. 77* F Same humidity and sunny for 3 weeks. Perfect weather for outside activities!