Good afternoon, There are no volcanoes that have ash plumes reaching interior Alaska today. So you can at least cross that off your possible culprit list. Have you checked https://akfireinfo.com/ ? -AVO Very fine sand or ash, do we have a nearby fire. I am located NE of Fairbanks on Gilmore trail at 1800 feet, it seems a little small for seed and is something I have not seen before, I have lived on Gilmore trail since 1974. Thank you