Severe thunderstorms are officially defined as storms that are capable of producing hail that is an inch or larger or wind gusts over 58 mph. Hail this size can damage property such as plants, roofs and vehicles. Wind this strong is able to break off large branches, knock over trees or cause structural damage to trees. Some severe thunderstorms can produce hail larger than softballs or winds over 100 mph, so please pay attention to the weather so you know when severe storms are possible. Thunderstorms also produce tornadoes and dangerous lightning; heavy rain can cause flash flooding. These hazards are covered in more detail under the tornado, lightning safety and flood safety websites.
Do you know the difference between a National Weather Service Severe Thunderstorm Watch and a Severe Thunderstorm Warning? Check your knowledge below.
- Severe Thunderstorm Watch: Be Prepared! Severe thunderstorms are possible in and near the watch area. Stay informed and be ready to act if a severe thunderstorm warning is issued. The watch area is typically large, covering numerous counties or even states.
- Severe Thunderstorm Warning: Take Action! Severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property. Take shelter in a substantial building. Get out of mobile homes that can blow over in high winds. Warnings typically encompass a much smaller area (around the size of a city or small county) that may be impacted by a large hail or damaging wind identified by an NWS forecaster on radar or by a trained spotter/law enforcement who is watching the storm.
Find out what you can do before severe weather strikes. Preparation is key to staying safe and minimizing impacts.
- Be Weather-Ready: Check the forecast regularly to see if you're at risk for severe weather. Listen to local news or a NOAA Weather Radio to stay informed about severe thunderstorm watches and warnings. Check the Weather-Ready Nation for tips.
- Sign Up for Notifications: Know how your community sends warning. Some communities have outdoor sirens. Others depend on media and smart phones to alert residents to severe storms.
- Create a Communications Plan: Have a family plan that includes an emergency meeting place and related information. Pick a safe room in your home such as a basement, storm cellar or an interior room on the lowest floor with no windows. Get more ideas for a plan at: https://www.ready.gov/make-a-plan
- Practice Your Plan: Conduct a family severe thunderstorm drill regularly so everyone knows what to do if a damaging wind or large hail is approaching. Make sure all members of your family know to go there when severe thunderstorm warnings are issued. Don't forget pets if time allows.
- Prepare Your Home : Keep trees and branches trimmed near your house. If you have time before severe weather hits, secure loose objects, close windows and doors, and move any valuable objects inside or under a sturdy structure.
- Help Your Neighbor: Encourage your loved ones to prepare for severe thunderstorms. Take CPR training so you can help if someone is hurt during severe weather.
Find out what you can do when severe weather strikes. Acting quickly is key to staying safe and minimizing impacts.
- Stay Weather Ready: Continue to listen to local news or a NOAA Weather Radio to stay updated about severe thunderstorm watches and warnings.
- At Your House: Go to your secure location if you hear a severe thunderstorm warning. Damaging wind or large hail may be approaching. Take your pets with you if time allows.
- At Your Workplace or School: Stay away from windows if you are in a severe thunderstorm warning and damaging wind or large hail is approaching. Do not go to large open rooms such as cafeterias, gymnasiums or auditoriums.
- Outside: Go inside a sturdy building immediately if severe thunderstorms are approaching. Sheds and storage facilities are not safe. Taking shelter under a tree can be deadly. The tree may fall on you. Standing under a tree also put you at a greater risk of getting struck by lightning.
- In a Vehicle: Being in a vehicle during severe thunderstorms is safer than being outside; however, drive to closest secure shelter if there is sufficient time.
What should you do when the lightning and thunder stops and it looks likes the severe thunderstorm is over?
- Stay Informed: Continue listening to local news or a NOAA Weather Radio to stay updated about severe thunderstorm watches and warnings. More severe thunderstorms could be headed your way.
- Contact Your Family and Loved Ones: Let your family and close friends know that you're okay so they can help spread the word. Text messages or social media are more reliable forms of communication than phone calls.
- Assess the Damage: After you are sure the severe weather threat has ended, check your property for damages. When walking through storm damage, wear long pants, a long-sleeved shirt and sturdy shoes. Contact local authorities if you see power lines down. Stay out of damaged buildings. Be aware of insurance scammers if your property has been damaged.
- Help Your Neighbor: If you come across people that are injured and you are properly trained, if needed, provide first aid to victims until emergency response team members arrive.