“Milky rain” has been drizzling over a dozen cities in the Pacific Northwest. The rain leaves a sort of sediment on inhabitants’ cars, jackets, and phones.
Affected cities include Spokane, Walla Walla, Ritzville, Coeur d’Alene, Pendleton, and Hermiston.
The Spokane National Weather Service and other officials are investigating the cause of the unusual drops. The National Weather Service also asked other agencies if they have samples.
Brown rain containing mud is fairly common in the summer during thunderstorms, said Weather Service forecaster Greg Koch, but “what was so unusual about this [milky rain] was not only that it occurred in the winter time, but it was a milky white or gray, which is very different than what we have around here.”
Koch speculated that the rain may have been caused by “a strong wind event in Northwest Nevada Thursday night, which continued into Friday, and that caused a lot of blowing dust in the Reno area and points north and east of there.”
The Nevada dust theory remains the most popular, as well as the most probable.
“[As we were] putting the pieces together, it seemed to be the most reasonable answer,” said Steve Bodnar, a meteorologist with the National Weather Service in Spokane.
“The fact that there was a big dust storm in a desert area with a lot of white soils kind of narrows it down,” Bodnar said.
The Weather Service’s other theories regarding the rain’s origins include “volcanic ash from Mexico or Russia . . . or perhaps ash from last year’s wildfires over SE Oregon/SW Idaho,” the Weather Service reported, and added that they still “don’t have a definitive answer.”