The public frequently confuses the difference between a tornado “watch” and a tornado “warning,” which can lead to delayed reactions when severe weather strikes. Understanding the precise distinction between these two alerts is fundamental for personal safety when atmospheric conditions are conducive to powerful storms. The National Weather Service (NWS) uses specific criteria for each term, and knowing what each implies translates directly into the correct, time-sensitive actions people must take.
Understanding the Tornado Watch
A Tornado Watch is issued when the atmospheric conditions are favorable for the development of tornadoes. This alert signifies that severe thunderstorms capable of producing rotation are possible, although no tornado has been sighted or confirmed yet. The Storm Prediction Center (SPC) in Norman, Oklahoma, issues these watches, which typically cover a large geographical region, often spanning numerous counties or even entire states.
The watch is generally issued for a period of several hours, providing advance notice that people should be prepared for potential severe weather. The appropriate response during a watch is to monitor the weather closely and ensure your emergency supplies and safety plan are ready. This is the time to gather a battery-powered radio, non-perishable food, and essential medicines.
Understanding the Tornado Warning
A Tornado Warning means that a tornado is imminent or is already occurring in the warned area. This alert is issued only when a tornado has been sighted by trained weather spotters or when Doppler radar has detected evidence of rotation within a storm. This level of alert indicates there is an immediate threat to life and property.
Local NWS forecast offices are responsible for issuing warnings, which cover a much smaller, specific area, sometimes only the size of a city or small county. Warnings are short-fused, typically lasting for 30 to 45 minutes. This alert requires immediate, life-saving action.
The Hierarchy of Threat and Required Safety Actions
A Tornado Warning is more dangerous and requires a more urgent response than a Tornado Watch. The watch serves as a heads-up to “be ready,” while the warning mandates that people “act now” to protect themselves from imminent impact.
When a Tornado Warning is issued, seek shelter immediately in the safest possible location. This involves moving to a basement, a storm cellar, or an interior room on the lowest floor of a sturdy building. People should avoid all windows, as these are the first things to fail during high winds, creating dangerous projectiles.
Put as many walls as possible between yourself and the outside. Once sheltered, individuals should get under something sturdy, like a heavy table, and use their arms, pillows, or blankets to protect their head and neck. Those in mobile homes or vehicles must leave immediately to find the closest substantial shelter, as these structures offer little protection against tornadic winds.
How Weather Alerts Are Disseminated
The National Weather Service (NWS) uses a system to transmit these alerts to the public. The alerts are broadcast through the Emergency Alert System (EAS), which interrupts radio and television programming. One of the most reliable methods is the NOAA Weather Radio (NWR), a nationwide network of radio stations that broadcasts continuous weather information.
Modern technology allows for alerts to be delivered directly to mobile devices via Wireless Emergency Alerts (WEA). This system, part of the Integrated Public Alert & Warning System (IPAWS), pushes the warning message to all compatible phones within the affected geographical area. Having multiple reliable methods for receiving these alerts is important, especially during the overnight hours.