It’s a potential hazard of amusement parks, state fairs, music festivals and other crowded venues — and terrifying for any parent: One minute your child is right beside you licking an ice cream cone, the next he’s gone.

Most kids don’t wander far. “Usually a child will go only a short distance, to check out the lights or cotton candy, for example,” says psychologist Eileen Kennedy-Moore, PhD, mom of four and author of “What About Me? 12 Ways to Get Your Parents’ Attention Without Hitting Your Sister.”

Even if he's only a few feet away, there's nothing amusing about losing sight of him. The best strategy: plan ahead.

Related: A Walk on the Wild Side: Keeping Your Kids Safe at the Zoo

Before you go

To avoiding losing your child in a crowd, Kennedy-Moore advises establishing ground rules ahead of time. “It’s easier to have rules in place before you head out the door, rather than try to establish them after your child has already gotten into trouble,” she notes. 

Nancy McBride, executive director of the Florida regional office for the National Center for Missing & Exploited Children (NCMEC), agrees. She recommends calling a family meeting about safety before you head out to establish simple, positive and specific rules. Tell kids what they should do rather than what they shouldn’t. For example, a simple rule like, “When you aren’t riding in the stroller, you need to hold onto it” will be easier for a child to understand and comply with than a more general statement such as “Don’t wander away,” says Kennedy-Moore.

Then be prepared to enforce the rules. This doesn’t mean threaten your child with punishment. It means make it easy for him to remember to follow instructions. If at the park he takes his hand off the stroller and starts to wander away, remind him of the rule and have him sit in the stroller or hold your hand for five or 10 minutes. Then let him try again to walk with you with his hand on the stroller. “Kids learn by doing it right, so a second chance is important,” says Kennedy-Moore. However, three strikes and he’s out: Your child isn’t ready for the responsibility of walking beside you at a park or fair and will need to ride in his stroller, period (assuming he's of stroller age).

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Beyond rules

Parents and kids can get separated in crowds for all sorts of reasons. Even if your child is the type who lives by the book, there are other precautions you can take to prevent losing him in a crowd. 

Bring backup. Bring along another adult if you can so you have an extra pair of eyes and hands. “If an older child is going with another family or on a group outing to an amusement park or other crowded venue, make sure there will be enough qualified supervision for all of the kids,” says McBride.

Make him glow. Don’t have your child wear the same plain t-shirt and baseball cap every other kid in the park will be wearing. Help him stand out in a crowd by putting him in a neon top. Then take a photo of him with your phone. This way you’ll have an image of him in his current outfit to show to others if he gets lost.

“But don’t dress you child in clothing that displays his name,” warns McBride. You don’t want a stranger to be able to talk to your child as if he's a family friend. Tuck an index card with your name and contact info on it into a pocket or pin it inside his shirt, she advises.

Be sure he’s got your number — your cell phone number, that is.“Any child old enough to memorize a song can memorize a ten digit number. In fact, setting your number to music will help,” explains Deborah Gilboa, MD, a family physician in Pittsburgh, Pennsylvania. If you’re not sure your child has the number down pat, use permanent marker to write it on a plastic clip-on bracelet for your child to wear on his wrist.

Survey your surroundings. As soon as you enter the park, look for a few spots that your child could easily find — the information booth in the center of the amusement park, for instance, or the giant Ferris wheel that towers over every other ride at the fair — and tell him if he gets lost to go to one of them and wait. Tell your child not to try to find you, to leave the grounds or go to the parking lot, adds McBride.

Help him recognize the right help. Your child also should know how to spot a grown-up he can trust — a policeman, a security guard or a park employee. “Have your child look around and see if he can identify folks who work there,” recommends Gilboa. Tell him to look for people with name tags or walkie-talkies, wearing uniforms or driving golf carts, for example. Tell him he also can approach a mom with a child — who will likely have a cell phone she can use to call you.

Related: Parents: 6 Lesser-Known Hazards to Heed

From lost to found

If you and your child get separated, report the situation at the information desk. Show the photo of him you took and describe any other details that might help others find him. (Does he have fresh ketchup stains on his shirt? Is he toting a stuffed animal you won for him?) Then head to the meet-up spot. Chances are, he’ll be there, clutching what's left of his ice cream.

Jennifer Kelly Geddes is a New York City-based writer and editor who specializes in parenting, health and child development. She’s also the mom of two teen girls.