At this time of year when the weather is hot and Lake Michigan‘s cool water is inviting, danger can ride in with the waves.

Beware of rip currents, those nearly invisible water flows that can sweep people far from shore. Beachgoers caught in the currents often panic, increasing the possibility of tragedy. Since June 14, 10 children under 17 have drowned in the Chicago area, several of them possibly as a result of a rip current.

Rip currents are sneaky. They move around, so beachgoers never know where they will be. And they are hard to see. The force of the current can push back against waves, making the site look calmer ­— and safer ­— than the rest of the beach. Inexperienced swimmers can actually be lured to the very site of a dangerous current.

But if you understand how the currents work, you can protect yourself by avoiding them, swimming out of them or — if you are not a good swimmer ­— simply staying out of the water on wavy days.

Rip currents form when strong waves sweep over a submerged sandbar near the shore. All that water has to get back out to the lake somehow, and it does so by forming a strong current. On a day when big waves are pounding in, the current can be so strong that even the best swimmers can’t make headway against it.

The secret is that rip currents, also called rip tides, are usually narrow. A swimmer can escape by moving a few strokes parallel to the beach. Once out of the current, you can swim back to shore.

Other tips for midsummer beach safety: Don’t swim alone. If you see someone caught in a current, notify a lifeguard, call 911 or throw a floating device into the current. Be careful: Many would-be rescuers die in the currents.

Enjoy the beach this summer — and be safe.