The pools are open, and Summer in northern Colorado is in full swing; so now it's more important than ever for parents to know that their kids can drown even after they've left the pool.

It may sound far-fetched, but secondary drowning is a real danger for swimmers.  It happens when water gets into the lungs, but doesn't start causing problems right away.

Check out the video above for more details on how to spot, and prevent, secondary drowning.