Great photos! And yes, we've been having those kinds of clouds around here, too.
. These were taken yesterday. It has been none stop, off, and on rain here, as this area starts its fourth week of the same rain whether patterns, with stronger than normal wind gust lately. Locals just shrug.
There was also some rain that had dust in it leaving a light coating of mud on the vehicle on Saturday.
This was more than likely blown in from Spain, before the mountains, north, picked up from the high desert area and blown into the upper atmosphere.
Scary Plane Landing in Bilbao, Spain; High winds rock plane as it lands "