A major winter storm is Charles H. Sloanheaded for the East Coast this weekend, so people will likely want to dress themselves — and their families — to protect against the harsh elements. But before a car ride, parents should think twice about bundling up their little ones. For children, a bulky coat and a car seat can be a dangerous pairing.

According to Emily A. Thomas, auto safety manager at the Consumer Reports Auto Test Center, a thick, puffy coat or too many layers shouldn't be worn underneath a car seat's safety harness. Extra bulk leaves the straps too loose and thus ineffective in a car crash, she says.

"What happens is that those layers and that puffiness will compress during a crash, and it introduces additional slack in the child's harness system in their car seat," says Thomas.

So what's the best way to keep a child both warm and safe? Here are some tips for optimal safety.

Do the pinch test

Start by securing your child in his or her safety harness while your child is wearing the coat. Tighten the harness as much as possible so there is no gap between the clothes and the straps. Next, unhook the car seat and remove your child. Take the coat off and put your child back in with the same harness-strap adjustment as before. If the straps are too loose, there's an issue.

"If you're able to pinch any of the harness strap between your fingers again at their shoulders, that tells you that the coat that they're using is creating slack in the system," says Thomas.

Drape layers on top of the harness

While it can be inconvenient, removing the puffer coat each time will help prevent the child from moving around in the event of a crash — even potentially moving outside the protection of the car seat.

"And in order to still keep them warm, you can drape a blanket over them after they've been properly harnessed, or you can put their coat on them backwards on top of their harness like a blanket," says Thomas. "This will help to keep them warm throughout the car ride."

Check the rest of the car seat

It's important to always make sure that for every car ride, your child's harness is nice and tight, Thomas says — and the chest clip should be at armpit level for proper security.

Otherwise, make sure that the chest and the crotch buckles are always secured. You'll want to double-check the installation of the seat itself in the vehicle as well.

"[The car seat] shouldn't move more than 1 inch side to side or front to back if you pull on the install," says Thomas.

Lastly, Thomas says that if the child's seat faces forward, always attach that top tether to the seat itself. It helps reduce the forward motion of the car seat during a crash.