Massive walls of dust and debris called haboobs that roll through the U.S. Southwest can be awe-inspiring and terrifying, especially for motorists caught in their path. Thunderstorms spawn the phenomenon and can create a wall of dust thousands of feet tall and several miles wide,

A massive dust storm swept through the Phoenix area on Monday afternoon, engulfing the city in an ominous, thick wall of dust and reducing visibility to near zero. Flights were grounded and thousands lost power as wind gusts reached 70 miles per hour in some areas.

After a very slow start to this year’s monsoon season, metro Phoenix has finally seen some storms this week — including a big one on Tuesday night. But was it a haboob? Or a monsoon? A dust storm? And what does it all mean for this very dry summer?