Frost Patterns

Whenever there is an overnight frost I tend to check for wind-blown frost patterns on my car. Usually if its been quite a sharp frost the vehicle will be covered in an overall white hoar frost. However, if the frost has only been around for as short time you can sometimes see the beautiful patterns as the frost forms. I assume they are caused by wind but I would be interested to hear from anybody who knows otherwise. Today was such a day so my first job having let the dogs out was to photograph the frost patterns on my windscreen. I was lazy and took hand-held shots so they are perhaps not as crisp as they might have been.

PS I have just googled window frost or fern frost and it is nothing to do with wind but a function of the way ice crystals grow on two dimensional surface where the outside temperature is lower than the temperature on the side of the glass. A bit like snow crystals but in two dimensions.