What distinguishes flash floods from downstream floods?
A) Flash floods are caused by thunderstorms, downstream floods do not involve lightning and thunder.
B) Flash floods occur in the upper part of a drainage basin, downstream floods occur in the lower part of a drainage basin.
C) Flash floods don't really involve any danger, downstream floods are extremely dangerous.
D) Flash floods are only common with large rivers, downstream floods generally involve much smaller rivers.

Question

Quizplus · Accepted Answer

Flash floods occur in the upper part of a drainage basin, while downstream floods occur in the lower part of a drainage basin. This distinction in location is what sets them apart from each other. Flash floods often occur quickly and unexpectedly after heavy rainfall in a small area and can cause significant stream flow in small streams located closer to the origin of the rainfall. Downstream floods, on the other hand, are caused by prolonged rainfall over a larger area, resulting in higher stream flows and flooding downstream.

What Distinguishes Flash Floods from Downstream Floods