This isn’t the Potomac River — it was Rock Creek on Monday morning. (Susan Hayward)

A strong line of thunderstorms with torrential rain flooded parts of the Washington region Sunday night. By the Monday morning commute, roads were waterlogged and some were completely impassable.

The squall line moved across the region from west to east after midnight Monday morning. Thunder and lightning woke many people up. Those that managed to sleep through the crashing and banging were probably jolted awake by cell phone alerts when a flash flood warning was issued for the western and then northern suburbs.

With significant moisture in the air, rainfall rates were able to top 1 inch per hour as the squall line moved through. Some locations, including Potomac and Arlington, received more than 3 inches of rain.

D.C.-area rainfall totals

Potomac — 3.52

Arlington — 3.4 inches

Laurel — 2.92 inches

Rockville — 2.91 inches

Dalecarlia Reservoir — 2.85 inches

Montgomery Co. Airport — 2.6 inches

Leesburg — 2.14 inches

Washington National — 2 inches

Baltimore-Washington International — 1.51 inches

Dulles International — 1.46 inches

Frederick — 1.34 inches

Andrews AFB — 1.31 inches

The Washington Post — 1.05 inches

Fort Belvoir — 0.44 inches