I listen to a police scanner thru headphones much of the day.

When we were told to evacuate the facility 5 years ago I knew that it was because of fumes from laying tile in a large building 5 miles away upwind and that the building was being re-occupied even as we were being shooed out of ours. The county reverse 911 told everyone within 5 miles to leave. So we did. Roads were clogged so badly all I could do was go around the block and back to my parking space. Walked across the street to the pizza parlor and had lunch. County was very embarrassed.

Another time I was listening to a deputy report swirling clouds in a thunderstorm over my building. Not a funnel yet but...
No PA announcement. I was the only one that had a clue.

During fire drills I listen to my Security people to see how it's going :-)

A scanner used skillfully is about your best bet.