Here is something you don’t hear every day. You may know that there are some horrendous forest fires burning out in Sonoma County, CA, northwest of San Francisco. Apparently the ash is falling so densely that it has caused a weather instrument that measures type of precipitation to report rain, although there is certainly none falling there today. The sensor works by look at optical scattering of a light beam, and the ash is disrupting the light beam, causing the instrument to think it is raining (it’s too warm to be snow). You can read more at SFGate here.
