Where to see snow in San Diego...?

I'm soliciting some advice here. Ever since Christmas, my kids have been talking nonstop about snowmen and snowflakes and other such snow-related things. In fact, Nolan has resorted to building snowmen in the backyard out of dirt clods (these are quite small snowmen) and empty nursery pots -- the kind for plants, including one gallons, five gallons, and the whopping 24" tree containers -- these snowmen can get quite large and elaborate, complete with athletic shoes and full-sized rakes in hand (click on the photo to see a larger image).

So, the next time we get a snowfall in the local mountains of San Diego County, where should I go to take my three kids (all under the age of five) to get a little dose of snow? All I need is a safe, flat area where they can make a snowball and a snowman, that's it.

Please be as specific as you can in describing your favorite spots. Thanks!