For individuals living in regions susceptible to severe weather, understanding the alerts issued by the National Weather Service (NWS) can be the difference between preparation and panic. These alerts communicate the level of atmospheric threat and provide a clear timeline for response. The two primary alerts for rotating storms—the Tornado Watch and the Tornado Warning—signify fundamentally different states of danger and demand distinct responses.
Tornado Watch: Conditions and Scope
A Tornado Watch is the initial alert, signaling that atmospheric conditions are favorable for the development of tornadoes in and near a specified area. This alert means that the necessary ingredients for severe weather, such as warm, moist air, and wind shear (wind changing speed or direction with height), are present. The issuance does not mean a tornado is currently forming or has been seen, only that the potential exists for one to occur.
The Storm Prediction Center (SPC) issues the Tornado Watch, and it is intended to provide a significant heads-up for a large geographic region. This area typically covers multiple counties or even several states, allowing for broad awareness. Watches are generally issued for a duration of four to eight hours, offering a window of time for people to prepare. This extended lead time is designed to shift the public into a heightened state of readiness.
Tornado Warning: Immediate Threat
A Tornado Warning signifies an immediate and severe threat, meaning that a tornado is imminent or occurring. This alert is issued when a tornado has been spotted on the ground by trained weather spotters or law enforcement, or when Doppler radar technology indicates strong low-level rotation within a thunderstorm. The shift from a Watch to a Warning indicates a confirmed hazard.
Unlike the Watch, the Warning is issued by a local NWS forecast office and is highly localized, covering a much smaller area, such as a single city or part of one county. This specificity is possible because the threat has been identified and tracked, allowing forecasters to pinpoint the hazard’s path. Warnings are short-term alerts, typically lasting for about 30 minutes, reflecting the rapid nature of the threat. A Tornado Warning can be issued even if a Tornado Watch was not previously in effect.
Response Protocol: What to Do Now
The difference between the two alerts dictates a distinct set of actions for public safety. When a Tornado Watch is issued, the appropriate protocol is to prepare and remain vigilant. People should use this time to review their family emergency plans, ensure they know the location of their safe room or shelter, and gather supplies like flashlights and water. Securing outdoor objects that could become airborne debris, such as patio furniture, is also a prudent step.
Once the alert escalates to a Tornado Warning, the response must change immediately from preparation to action. The priority is to seek shelter without delay in a basement, storm cellar, or an interior room on the lowest floor of a sturdy building. Stay away from windows, and covering the head with a mattress or heavy blankets can provide protection from flying debris. Those in vehicles or mobile homes must abandon them and seek the closest substantial shelter or lie flat in a ditch, as these structures offer little protection against tornadic winds.