canaries in the coal mine
Early danger detectors
Canaries in the coal mine are early warning signs of danger or trouble.
Miners once brought canaries underground because the birds would die from toxic gases before levels became lethal to humans—a dead canary meant get out.
Now the phrase describes anything that signals problems before they become obvious: Rising dropout rates are canaries in the coal mine for the education system.
- warning signIndicator of potential danger
- signMark conveying information
- writing on the wallObvious omen of trouble
- indicatorSign revealing status
- alarmUrgent warning signal
wake up call · sentinel · red flag · forewarning · tip of the iceberg · idiom · hazard assessment · detector · analogy · figure of speech · symbol · harbinger · allegory · monitor · trope · occupational hazards · toxic gas · imagery
canaries in the coal minehindsight
Recognition after the fact
too little too late · crying wolf · head in the sand · willful blindness · rearview mirror
canaries in the coal minecollateral damage
Unintended harm from military action
canaries in the coal minefalse alarms
Warnings without danger
red herrings · paper tigers · empty threats · clean bill of health · green light
canary, canaries, coalminer, coalminers, coalmine, coalmines