A slope is when the land slants downhill (and uphill, for that matter). On long, steep slopes, runoff water moves very fast. And the faster runoff water moves, the more it digs into the soil. It grabs soil particles and washes them down the hill, causing more erosion.
This means erosion is a bigger problem on long, steep slopes than on shorter slopes and flatter ground. But erosion can still happen on short slopes if the soil is not protected.
Runoff water steals soil. Erosion is worse on long, steep slopes than on shorter, flatter slopes.
Photo: USDA NRCS