Flash flooding caused a large mudslide that covered part of State Route 821 in the Yakima Canyon, 6 miles south of Ellensburg, and forced the closure of the highway late Tuesday. 

The road was closed 17 miles north of Selah to Ellensburg and could be closed for several days, the state Department of Transportation said.

Kittitas County Undersheriff Clayton Myers said the landslide was about 100 feet wide and 15 feet deep.  No injuries or stranded vehicles have been reported, he said.