The cities of Wheat Ridge and Lakewood will test their emergency sirens on May 10 at 11 a.m.

Here’s the big thing: Don’t be alarmed.

It will be loud, as these things are supposed to warn about dangerous weather, flash floods, chemical spills and more. The alert will sound like a long wail, followed by a spoken announcement, wrapping up by about noon.

And what should you actually do when you hear this type of siren? If you’re anywhere in the Denver metro, you can tune your radio to 850 AM or check television news to see what’s happening.

Don’t call emergency services. Do take shelter if there’s reason to believe this is a tornado situation.

Frankly, one of the best things you can do is sign up for reverse 911 at your911.net, which will allow you to get relevant emails and text messages in emergency situations.