Write a brief scene in which both snow and sand make an appearance.
Yes, this prompt really is just that simple. There are dozens of ways to spice it up or restrict it further, however, if that isn’t enough for you. Place limits based on writing time or space. Specify a genre. Specify that both the snow and the sand have to be real parts of an outdoor scene, actual conditions, not represented in some other way. Do whatever you want with it!