Winter storms cause the Chehalis River to flood many cities in Lewis County, Washington, and close a 20-mile portion of Interstate 5 for several days. At least eight deaths and billions of dollars in damages are blamed on the floods.

The Chehalis River ( shə-HAY-lis)

is a river in Washington in the United States. It originates in several forks in southwestern Washington, flows east, then north, then west, in a large curve, before emptying into Grays Harbor, an estuary of the Pacific Ocean.

It was once much larger during the Ice Age when the tongue of the glacial ice sheet covering the Puget Sound terminated near Olympia and glacial runoff formed a large torrent of meltwater. This carved a large oversized valley that is much larger than the current river could have produced. The river's mouth was out near current Westport until rising sea levels at the end of the ice age flooded the broad Chehalis Valley to form a ria, known today as Grays Harbor.