It’s officially summer — at least meteorologically speaking. The calendar won’t tell us it’s summer for another few weeks, but children are out of school, and it’s hot — that’s summer enough.

And with the arrival of summer comes a danger that is too often overlooked — drowning. Every day, about 10 people in the U.S. die from drowning. Of these, two are children 14 or younger.

But it turns out, most of us probably don’t know what drowning looks like. It’s not the violent splashing you would expect, according to Mario Vittone, a marine safety specialist with the U.S. Coast Guard. Drowning is almost always deceptively quiet, Vittone says.

“The waving, splashing and yelling that dramatic conditioning prepares us to look for, are rarely seen in real life,” she wrote.

Why? It has to do with the Instinctive Drowning Response, a set of behaviors that take over automatically when a person is drowning.  It’s a noiseless process with subtle movements.

“A person at, or close to, the point of drowning is unable to keep their mouth above water long enough to breathe properly and is unable to shout. Lacking air, their body cannot perform the voluntary efforts involved in waving or seeking attention. Involuntary actions operated by the autonomic nervous system involve lateral flapping or paddling with the arms to press them down into the water in the effort to raise the mouth long enough to breathe and tilting the head back,” according to a U.S. Coast Guard Search and Rescue journal.

“From beginning to end of the Instinctive Drowning Response people’s bodies remain upright in the water, with no evidence of a supporting kick. Unless rescued by a trained lifeguard, these drowning people can only struggle on the surface of the water from 20 to 60 seconds before submersion occurs.”

We all should know the signs of drowning. They are:

• Head low in the water, mouth at water level

• Head tilted back with mouth open

• Eyes glassy and empty, unable to focus

• Eyes closed

• Hair over forehead or eyes

• Not using legs

• Hyperventilating or gasping

• Trying to swim in a particular direction but not making headway

• Trying to roll over on the back

The easiest way to determine if a swimmer is in trouble is to ask them. If they can answer, then things are probably fine. If they can’t, you only have a few seconds to save them, according to Vittone.

“Remember – children playing in the water make noise,” she wrote. “When they get quiet, you get to them and find out why.”