What is the difference between Tornado Watch and Warning?

Tornadoes are devastating storms with winds that can reach more than 300 miles per hour, flattening homes, neighborhoods and entire towns.

Tornadoes develop quickly, and the precise path and location can’t be predicted with 100 percent certainty. That’s according to Bill Bunting, deputy director of the National Oceanographic and Atmospheric Administration (NOAA) and the National Weather Service (NWS) Storm Prediction Center (SPC).

That’s where tornado watches and tornado warnings come in. Though tornadoes are unpredictable, Bunting says, “identifying an area at risk a day or more in advance is often possible.” That’s critical.

Aaron Treadway, NWS severe weather program coordinator, says the earlier the public can be informed of a potential tornado-producing storm, the better. “Once someone is aware that tornadoes will be possible in the coming days, there are several steps they can take to better prepare,” Treadway says.

The keys: Communicate with family members, make alternate plans and know where you’ll shelter before weather threatens. Here, Bunting and Treadway explain what to do when you get that tornado watch or warning.

About the Experts

Bill Bunting is the deputy director of the NOAA/NWS Storm Prediction Center in Norman, Oklahoma. As a meteorology student, Bunting participated in the original Toto (Totable Tornado Observatory) project, memorialized in the movie Twister.

Aaron Treadway serves as the NWS severe weather program coordinator at the NOAA/NWS headquarters in Norman, Oklahoma. Treadway gained valuable experience observing tornados in 10 years as an operational forecaster at the NWS office in New Braunfels, Texas.

What Is a Tornado Watch?

Tornado watches alert people that conditions are favorable for tornadoes. It doesn’t mean tornadoes have formed, or one is imminent. It means severe thunderstorms capable of producing tornadoes could be forming, often along with strong winds, hail or even flash flooding.

Bunting says watches cover large areas multiple counties, entire states or even several states at a time. They’reissued by the SPC, which is responsible for watches across the entire country.

Because tornado watches are intended to give the public time to prepare, Treadway says they’re typically issued a few hours before the threat is expected to arrive. They last about four to seven hours, Bunting says. Under a tornado watch, people should “monitor weather information more frequently, as severe storms begin to develop or move into the watch area,” he says.

How to respond to a tornado watch

Only a small percentage of thunderstorms actually produce tornadoes, Bunting says. But when a tornado watch is issued, it’s important to follow these steps.

• Tune to local weather broadcasts:“TV continues to be one of the best ways to get additional weather information during active weather,” Treadway says. Tornadoes can happen quickly, so “even as more people stream, these local TV stations and their weather coverage continue to be a go-to” during severe weather, he says. If you cut the cord, Treadway says, “[m]ost local news stations now stream live on their website during active weather.” So check that first.
• Have multiple information channels: “On the day of the tornado threat, the biggest thing is to have multiple ways to get any potential tornado warnings,” Treadway says. Even if you have your TV tuned to local wall-to-wall coverage, download weather apps on your smartphone, check social media frequently and consider buying a NOAA Weather Radio, which broadcasts on a special “weather band” frequency range. They’re available at home improvement centers, boat and camping stores and online. Treadway can’t endorse specific commercial weather apps, but says “the vast majority of radar apps are simply using the NWS network of radars” and raw data. Treadway says the Federal Emergency Management Agency (FEMA) app is a good one, with weather info, alerts and disaster prep.
• Discuss emergency plans: Know how to quickly get to safety. Charge phones and make sure everyone in your family knows where to go if a tornado warning is issued. Enable your family’s phones to receive wireless emergency alerts (WEA), which operate like Amber Alerts. These will inform you of severe weather and other emergency information.

One important note: If you live in a mobile home and a tornado watch is issued, act immediately, Treadway says. Go to your community tornado shelter or other sturdy building, like a friend’s house or nearby business. “For folks who live in a mobile home, even a weak tornado can do significant damage,” Treadway says.

The NWS has more tips for mobile home safety during a tornado.

What Is a Tornado Warning?

A tornado warning means a tornado is happening now, or there’s an imminent threat of a tornado.

Tornado warnings are issued “when a tornado has either been spotted and reported to the NWS, or our weather radars give an indication that a tornado is either developing or ongoing,” Treadway says. Tornado warnings are issued locally by 122 local NWS forecast offices. They cover smaller areas than tornado watches.

Local NWS meteorologists use Doppler radar, a system based on the Doppler effect,and storm spotters to track severe storms before issuing warnings, Bunting says. Warnings are typically in effect for 30 to 60 minutes and cover portions of a county, parish or independent city.

How to respond to a tornado warning

Don’t wait. Tornadoes are unpredictable and life-threatening. “When a warning is issued, the time to prepare is over,” Treadway says. “Warnings mean to take action get to shelter!”

Here’s what to do:

• Seek shelter immediately:Get to the interior of a well-constructed building. “If possible, a basement or storm shelter are the best options,” Treadway says. If not, a first-floor interior closet or bathroom is a good choice. Put as many walls between you and the flying debris of the tornado as possible.
• Stay away from windows: Don’t look out or go outside to see where the tornado is, and don’t open the windows it’s a myth that this “equalizes” the pressure. Once you’re in your shelter, stay there.
• Get low and cover your head:Protect your head and neck with helmets, pillows, towels or a mattress. Wear shoes to protect your feet from broken glass and other sharp objects.
• Listen for weather updates:Keep your NOAA weather radio tuned to the appropriate channel, or watch your phone for new WEA or other important weather information.

If you’re outside, or in your car, “the instructions are still the same get off the road and get inside,” Treadway says. “A vehicle, or outside under an overpass, are not adequate shelters!”

Abandon mobile homes and get to a safe structure. If you are in imminent danger and there is no adequate shelter nearby, lie face down in a ditch or depression, away from trees, and cover your head with your hands.

What is a Tornado Emergency?

Treadway says in rare cases, a tornado emergency will be issued if there’s a confirmed, violent tornado in progress that threatens human life and/or could cause catastrophic damages. This is a tornado warning, but with “enhanced and urgent wording” to emphasize the severity, Treadway says. Take the same immediate actions you would for a tornado warning.