Well, cinders from an oil burner might be tough to do (coal does a much better job of that), but soot coated sand happens a lot!

I've always noticed that the large crowds that clog the open cars often disappear once the cinders, sand or whatever falls from the sky. Throw in some rain or snow, you soon see who the real diehards are.

I'm rather amazed at the touristas that climb aboard completely unprepared for changes in weather. "Gosh, they never told us it might snow at 10,000 feet in Colorado in September..."

sda