Spring break -- the collegiate ritual, the parental horror show, the thriving industry -- is here. And given the varying schedules of our nation's college campuses, it will be with us, for better and for worse, through early April.

Like an ineradicable weed, the tradition is driven by powerful biology and fueled by exposure to sun and water through deceptively complex roots. And yet, unlike an ineradicable weed, its history includes George Hamilton, Sonny Bono and a staggering number of sons and daughters of California.

Between now and April 6, thousands of California college students will head to Mexico, Las Vegas or Lake Havasu in Arizona. An estimated 225,000 revelers are expected in Panama City Beach, Fla., the unofficial North American capital of spring breakage.

And smaller versions ("more modest" would be the wrong phrase) of the same scene will erupt -- often with the encouragement of civic leaders who can't resist the cash infusion -- at Miami's South Beach, Key West and Daytona Beach in Florida; South Padre Island in Texas; Myrtle Beach in South Carolina; and Jamaica and the Bahamas.

Mexico lures many with its legal drinking age of 18, rather than the usual 21 in the U.S. And tour operators and resort companies woo students by assembling packages that bundle airfare, lodging, meals, access to "VIP" rooms and often drinks as well. Wander into any spring-break zone and you'll find that even the most scantily clad celebrants are sporting color-coded plastic bracelets to affirm their party privileges. (And even if spring-breakers don't buy a tour operator's package, in Mexico they're likely to find clubs that charge $25 to $35 for admission, then serve beer at no charge.)

To be sure, these partying legions are but a small part of the 17 million U.S. college students. And many young people fill their spring breaks in wholesome and constructive ways.

But when March rolls around each year, the deeds and misdeeds of the spring breakers can be striking and profitable (especially for operators of nightclubs) and scary (especially if you're one of their parents).

The U.S. State Department, which estimates that more than 100,000 American teenagers and young adults travel to Mexico for spring break each year, notes that although most students enjoy themselves, "several may die, hundreds will be arrested, and still more will make mistakes that could affect them for the rest of their lives."

Inevitably, the mix of free-flowing alcohol and rampant hooking-up will yield profound headaches, sunburns and varying degrees of embarrassment, some involving video footage. And some of the trouble will go deeper: money lost to dodgy travel companies; injuries; arrests; and perhaps worse.

"Probably 98% of our kids don't get into any sort of trouble," says Thomas Betz, an attorney with Student Legal Service serving the 41,000-student University of Illinois campus in Urbana. But in 23 years of legal service to spring-breakers fleeing chilly Illinois, Betz said, he has reckoned with everything from jellyfish stings to hot-tub burn (something to do with over-chlorination) to Mexican incarcerations.

If a student is caught buying drugs in Mexico, Betz said, "that's when all hell breaks looses." He tells families to hire a Mexican attorney immediately -- big hotels often keep a list at the desk -- and expect to pay $500 to $2,500 in bail and fines if the offense is a small amount of marijuana. If it's a large amount, or a stronger drug, Betz said, it gets worse.

Kristen Celko, vice president of marketing and e-commerce in North America for the global student travel agency STA Travel, calls spring break "the biggest international movement that you have during the school year." At STA, which has 11 offices in Southern California, year-over-year spring-break numbers continue to grow, she said, surpassing those for Thanksgiving or New Year's Eve.

Acapulco, Mexico, is especially strong this year, Celko said, drawing students from East and West coasts. (It accounted for about 25% of STA's spring-break packages sales this year; a typical package costs $500 for round-trip airfare and four nights' shared lodging.)

But Costa Rica is coming on as well, Celko said, with spring bookings up 21% from last year. If this continues, "I think over the next few years, we'll see [Costa Rica] as the No. 1 or No. 2 destination for spring breakers from the West Coast," Celko said.

Among U.S. spring-break destinations, several industry veterans say, Las Vegas has been gaining ground.

The attraction is no great mystery, especially with flights so frequent and relatively inexpensive, and rooms plentiful. The problem with so many students going to Las Vegas, said Illinois attorney Betz, is "most of them are not of legal age to gamble, and most of them cannot legally drink, either. Somehow there's this assumption that if there are enough of you there, this [legal barrier] will all go away."

As a result, Betz says, he sees a lot of "drinking under-age" cases (which typically result in fines), but things get worse when students are caught with fake identification, which can put them "in the felony zone."

If you or somebody on your insurance policy is considering a venture into the world of spring-breakery -- or if you're looking to stay out of the din -- here are a few things to know about seven popular spring break destinations:

Lake Havasu City, Ariz