Large Nevada dust storm, which occurred Thursday night into Friday, is the primary suspect for unusual milky white and gray rain that started falling on parts of northwestern US late last week.
National Weather Service began reporting this unusual phenomenon on Friday, February 6, 2015. At least a dozen towns in the Northwest confirmed the presence of thick milky white and gray rain.
It is not unusual to experience "muddy rain" in the Inland Northwest, writes the Inland Northwest Weather Blog. "During the summer months, dirty brown water marks are frequently deposited on our cars. However, muddy rains rarely occur in the winter. And why the unusual milky white color?"
On Thursday night into Friday, numerous reports of blowing dust and winds gusting in excess of 60 mph (96 km/h) came from Washoe, Humboldt, Pershing, Churchill, and Lyon counties which are generally sparsely populated counties experiencing a multi-year drought.
"Check out some of the pictures from the Reno Gazette-Journal posted in a Saturday story about the storm that pounded the Sierra Mountains with snow and produced strong winds in western Nevada. Note the milky white or grey color of the blowing dust," Inland Northwest Weather Blog wrote.
- See their detailed analysis here.
Other possible causes include several volcanic eruptions, from South America to Russia's Far East, and ash from burn scars in the Western US.
The mystery, however, won’t be solved until scientists finish chemical analysis of the rainfall.
Featured image credit: NWS Spokane