Developed for the powder-chasing skier or snowboarder, Snowmap is a key tool for your weather toolkit. It will hopefully help you in understanding where and when the best snow will fall.
Snowmap provides an iPhone and iPad optimized interface for viewing probabilistic forecasts from the NOAA/National Weather Service Weather Prediction Center. These forecasts show you the probability a particular amount of snow (ranging from 1" to 18") will fall within an area on the map, in 6 hour increments over the next 2-3 days.
Finally, Snowmap includes the locations of 450+ ski resorts in the USA and Canada, so you can easily see the best destination to take advantage of an incoming storm.