Related Clues:
- Warning of a sort
- Screamer at a crime scene
- Klaxon
- Like good guards
- All-points bulletin, e.g.
- Security warning
- Fire station signal
- Wail that warns
- Eagle-eyed
- Siren, for one
- Standing at the ready
- Clock radio setting
- Sign word that may be followed by an exclamation point
- More than just startle
- Shout "heads up!"