| Answer | Crossword Clue |
|---|---|
| RADAR | Modern warning system. |
| RADAR | Warning system. |
| RADAR | Warning system |
| BELL | School warning system |
| DEWLINE | Early-warning system. |
| DEW | ... line (early warning system) |
| DEWLINE | U.S. warning system |
| RADAR | U. S.-Canadian warning system. |
| SWORDOFDAMOCLES | WARNING: Suspension system prone to failure |
| CLIMATECANARY | Species that serves as an early warning system |
| NORAD | Early warning system for the U.S. and Canada |
