(Bill O'Leary/THE WASHINGTON POST)

The Fourth of July brings fireworks, barbecues, patriotic band music and lots of flag-waving crowds. For families of some children with autism or sensory processing difficulties, all of that holiday “fun” can be a recipe for a meltdown.

The noises, smells and crowds can be overwhelming and send a child with autism into sensory overload, said Aviva Weiss, a mom of six and an occupational therapist in Merion Station, Pa. Weiss is also the founder of Fun and Function, a company that designs toys and therapy equipment for children with special needs.

“If families are going to be doing something different from what they usually do, those changes can be difficult for kids with sensory difficulties and autism,” Weiss said.

Some families may choose to avoid the festivities, opting to watch fireworks online or on television instead, and have a quiet celebration at home. That’s fine, Weiss said.

“Every family has to make the decision that is best for them,” Weiss said. “Some families should not engage in activities that are overwhelming for them and their children. If it means that everyone is going to need to take a Valium the next day, it’s not worth it.”

But families who want to venture out can with a few simple preparations, she added. The key is to know your child’s limits and have an escape plan in case he needs a break.

“If you discuss it [with your child] beforehand and say, ‘It’s okay if you get scared or sad or anxious, and I’m going to help you,’ you’re already mitigating it a lot by letting your child know you are there for him,” Weiss said.

Here are some of Weiss’s suggestions for enjoying the holiday with a child with sensory difficulties.

Prepare and practice. Talk about exactly what you will be doing: getting in the car, taking a picnic, eating, watching fireworks, walking back to the car, waiting in traffic and any other details you can think of. The more your child knows what to expect, Weiss said, the better he will likely respond.

Take things to help reduce the noise or stress, such as earplugs or noise-canceling headphones, a squeeze ball, things to chew, a special stuffed animal or a weighted lap pad.

Watch videos of fireworks online or make loud noises with pots and pans and have him come up with ways to reduce his stress.

Let him choose. If there is somewhere else he can go during the fireworks, give him the option of staying back while the family goes out. If he does decide to come with the family, give him a choice of where to sit, or ask if there is something special he would like to wear that would make him more comfortable.

“Having choices is very empowering,” Weiss said.

Make him comfortable. Take comfortable seating for your child, whether it’s a reclining lawn chair or a gel seating cushion. A small pop-up tent may help give your child a sense of security and distance from the crowds. Finding a quiet spot to watch from afar can help, too.

Give him a job to do. Weiss suggests having your child be in charge of taking pictures at the event or passing out food. Having a task can help him feel like he is in control of something.

Have an escape route. Park nearby, if possible, so you can escape to the car if your child gets overwhelmed. Tell him to let you know if he’s had enough and that it’s okay if he needs to leave. Have soothing music or a favorite toy in the car to help him calm down.

“Your child may have a meltdown and other people may look at you,” Weiss said. “Being okay with that takes a lot of strength. If that can happen, you’re calmer in the way you handle the situation.”