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 .... http://www.komonews.com