A massive Sahara dust cloud, 2,000 miles wide, heads toward the southeastern U.S., affecting air quality.

A vast dust cloud from the Sahara Desert, about 2,000 miles wide, is expected to reach Florida and the southeastern U.S. by Wednesday. Known as the Saharan Air Layer, this dust is carried by low-pressure waves from Africa and can cause hazy skies. While most dust remains high in the atmosphere, rain may deposit it on the ground. The dust also suppresses tropical storms. Florida faces additional air quality issues from Canadian wildfire smoke.