Mysterious "dirty rain" falling in Eastern Washington, Oregon

komonews.com While it's been a routine, rainy day in Seattle, those over in southeastern Washington and northeastern Oregon have had a strange phenomenon: A dirty, milky rain. Several reports have come in from Spokane, Walla Walla, Pendleton -- and really across much of that region. The rain has left a dirty residue on cars and has flooded social media over there with people wondering what is causing the odd rain. So far, the official cause remains a mystery, but officials with the National Weather Service offices in Spokane and Pendleton are looking into it.