Warning literacy

Tornado warning language decoded

NWS warnings use specific language. Most people don't know what "considerable" means. Here is the actual definition of every phrase.

The tags

TORNADO WARNING (base)

A tornado is imminent or occurring. Take cover.

CONSIDERABLE

Radar-confirmed rotation with damage-producing potential. Take cover NOW.

CATASTROPHIC

Rare highest tag. Long-track violent tornado on the ground. Life-threatening.

TORNADO EMERGENCY (rarest)

Historical tag. Confirmed violent tornado in populated area. Extreme danger.

The IBW (Impact-Based Warning) history

2012 pilot in Central Region.
2014 nationwide adoption.
Purpose: differentiate routine warnings from extreme ones.
Response: research shows some improvement in shelter-taking rates.
Debate: does it help or does it desensitize routine warnings?
Actively refined by NWS.

The confirmation levels

Radar-indicated

Radar shows rotation. No visual confirmation.

Spotter-confirmed

Trained spotter sees tornado.

Public-reported

Untrained observer report.

Damage survey confirmed

Post-event damage inspection.

Debris signature confirmed

Dual-pol radar shows lofted debris.

The threat categories

Wind: EF-scale estimates in warnings.
Hail: quarter, half-dollar, golf ball, tennis ball, baseball.
Damage: mobile homes, wooden buildings, trees.
Injury/fatality: rarely explicit.

What "TAKE COVER NOW" means

The phrase is precise:

Interior room, lowest floor.
Away from windows.
Small room preferred (bathroom, closet).
Bring shoes, hardhat, blanket.
Kids and pets included.
Stay until all-clear.
Do NOT try to observe the tornado.
Do NOT drive.

Common misunderstandings

"Warning" is only a possibility → actually means imminent.
"Radar-indicated" means low risk → actually just means no visual.
"Small tornado" is safe → EF0 winds still 65-85 mph.
"Watch" means tornado is happening → no, means conditions favorable.
"Warning ended" means safe → additional cells may follow.

When to shelter

Immediately on tornado warning.
Consider sheltering on strong severe thunderstorm warnings.
Any warning tagged CONSIDERABLE or CATASTROPHIC = drop everything.
Multiple warnings mean cyclic system — stay sheltered.
Warnings for nearby counties can affect your county before official upgrade.

If the warning ends

Do not leave shelter for at least 5 additional minutes.
Check radar for follow-on cells.
Monitor NOAA Weather Radio.
Look for green sky signals.
Post-tornado damage inspection: wait for all-clear.
Do NOT rush to help unless emergency responders are absent.

Warning delivery channels

Wireless Emergency Alerts (WEA)

Phone alarm. Cannot silence unless disabled.

NOAA Weather Radio

SAME-programmable radio. Best while asleep.

TV/Radio EAS

Broadcast interrupt.

Outdoor sirens

Some communities.

Weather apps

AccuWeather, Weather Underground, RadarScope.

Text alerts

Municipal.

Family communication

Backup for the vulnerable.

For deaf / hard-of-hearing

Vibrating weather radio (Midland WR-120 with bed shaker).
Flash-strobe home alarm.
WEA visual alerts on phone.
Community buddy system.
Register with county for high-priority alerts.