Terrain parks are like opinions - just about everybody's got one. According to statistics compiled by National Ski Areas Association, almost 90 percent of all winter mountain resorts in the United States have some sort of terrain park.

California is no exception, with the majority of its two dozen resorts having some sort of terrain park.

"Resorts have come to the conclusion that terrain parks are on the list of to-do options," says Mike Bettera, senior projects manager of Snow Park Technologies, whose clients include the Winter X Games in Aspen. "Terrain parks are something you must have."

Loosely defined, a terrain park is a special, set-aside area of a resort that allows skiers and snowboarders to play on in-snow features such as rails, boxes, stairs, and other similar (generally metallic) protuberances. Park rats, as the generally youthful TP denizens are called, then slide across, bounce off, or jump over these features with varying degrees of skill and a great amount of enthusiasm.

"It's totally a social thing," says Bettera. "It comes from urban skateboarding where kids like to simply hang out. It's truly different from the backcountry (skiing and snowboarding) experience."

Like opinions, terrain parks also vary greatly.

"A good park is one that has multiple levels of progress," says Bettera. "You have small, non-intimidating features for (neophytes) getting the feel of going over them. Then you have medium-size features that create a good line with multiple hits that are fun for people no matter how (well) they ride. And then you have large features for the show boats to dial in big tricks.

"You can tell the better parks by the amount of (commercial) branding they use. And by the way they look and are presented through the use of flags, fencing, music, animation and other fun stuff...things that bring liveliness and life to the park."

On the other hand, Bettera says, you can tell when a resort just doesn't care about park rats.

"There's not a lot of allocation of resources," he says. "They don't maintain the park on a daily basis or the trail is hidden or is not pushed or marketed by the resort or it's not (commercially) branded."

Here's a brief rundown on what California has to offer in the way of terrain parks:

Northstar-at-Tahoe has perhaps the most ambitious project with separate parks. There's the main one on Pinball that has medium-size features and is the most populated. There's also a Burton Progression Park that's just right for newbies and a giant-feature run on Moonshine. Don't forget the Stash, a mostly-in-the-trees park that incorporates many natural or natural-looking features.

Bear Mountain has installed 15 jumps and 80 jibs on its 748 acres of rideable terrain spread out over four mountains. Lights have made night jibbing a popular Southern California pastime.

Boreal Mountain Resort, home of the legendary Jibassic Park, has devoted nearly 100 percent of its terrain to jumps and other park features, making it the sole all-mountain terrain-park resort in Northern California.

Mammoth Mountain's immensely popular Unbound Terrain parks consist of three separate areas (divided by ability) spread over 90 acres. The parks combine for 50 jibs and 50 jumps and include one humongous super-pipe.

Heavenly has five separate areas for park rats to play in: A small-feature zone off the Groove chair, three medium-feature areas off the Powder Bowl, Tamarack and World Cup chairs, and a large-feature playground off the Canyon chair.

Alpine Meadows has three man-made-features parks - a beginner's area off the Tiegel poma and two tougher ones, collectively known as the Shreadows, off the Kangaroo chair - and a Mother Nature's own terrain-park playground in Hot Wheels Gully.

Mountain High, Southern California's favorite snowboarding playground, has a variety of parks at the West Resort to suit every ability. There are three separate parks for beginners off the parallel Coyote and Roadrunner chairs; a couple of medium-feature (and a pipe) riders' right of the Blue Ridge Express lift; and one for more ambitious riders on the Upper Chisholm run.

Read Paul Doherty's There's A Terrain Park For Everyone - Adrenaline Junkie Or Not for a library of information on North American terrain parks, including links to relevant stories.