Water vs Snow

I was watching the local news the other day when they measured the snow pack to see how much trouble we will have with drought. The snow pack was quite low and they are talking about drought measures that may need to be taken... things like watering lawn, not flushing as often, no boating on the lakes.

I had a random thought pop in my mind as they showed the background of the story -- skiers going down the snowy mountain side. I thought to myself "I wonder how much water it takes to make the snow that they are skiing on." Because of the lack of snow so far this season many of the resorts make their own snow. I want to know where they get that water??? Do they drain local reservoirs? Take it out of Lake Tahoe? American River run off?

I would like to see the numbers. How many gallons of water is wasted so that people can ski?