What are we supposed to do when we hear an outdoor warning siren?

I bet you came up with a very situational protocol, such as: go in the basement, a tornado is coming.

Let’s reframe the narrative - warning sirens are ment to alert you that there is an imminent threat to human life and you need to get more information. tl;dr: take cover and tune in.

For more info from the National Weather Service: https://www.weather.gov/dvn/sirenFAQ