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Thunderstorms & Hail
All thunderstorms are dangerous and every thunderstorm produces lightning. The Southeastern United States is very likely to have lightning and thunderstorms, especially in the summertime.
Development
Thunderstorms are the result of convection in the atmosphere. They are typically the by-product of atmospheric instability, where air masses of varying temperatures meet. Rapidly rising warm moist air serves as the engine for thunderstorms.
Characteristics
A typical thunderstorm can be three miles wide at its base, rise to between 40,000 to 60,000 feet in the troposphere, and contain half a million tons of condensed water. Conglomerations of thunderstorms along cold fronts (with squall lines) can extend for hundreds of miles.
Thunderstorms contain tremendous amounts of energy derived from water condensation. According to the National Weather Service, a thunderstorm is classified as severe when it produces one of three elements:
- A tornado
- Hail at least 0.75 inches in diameter
- Winds at least 58 miles per hour
Occurrence
While thunderstorms can occur in all regions of the United States, they are most common in the central and southern states because atmospheric conditions in these regions are most favorable for generating powerful storms.
Hail
Hailstorms are a potentially damaging formation of severe thunderstorms. Hail is created when strong rising currents of air within the storm, called updrafts, carry water droplets to a height where they freeze.
Ice particles will continue to grow in size, eventually larger than .75 inches causing them to become too heavy to be supported by the updraft and fall to the ground.
Hail is larger than sleet and will only form inside a thunderstorm. The size of the hailstones is a direct function of the size and severity of the storm.
Thunderstorm and Lightning Safety
Before Thunderstorm and Lightning
- Remove dead or rotting trees and branches that could fall and injure people or damage property.
- Delay outdoor activities.
- Remember the 30/30 Lightning Safety Rule: Go indoors if, after seeing lightning, you cannot count to 30 before hearing thunder. Stay indoors for 30 minutes after hearing the last clap of thunder.
- Secure outdoor objects that could blow away or cause damage.
- Get inside a home, building or hard top vehicle (not a convertible). Although you may be hurt if lightning strikes your car, you are much safer inside a vehicle than outside.
- Remember, rubber-soled shoes and rubber tires provide NO protection from lightning. However, the steel frame of a hard-topped vehicle provides increased protection if you are not touching metal.
- Shutter windows and secure outside doors. If you can’t find shutters, close window blinds, shades or curtains.
- Unplug any electronic equipment well before the storm arrives.
- If in a forest: Seek shelter in a low area under a thick growth of small trees.
- If in an open area: Go to a low place such as a ravine or valley. Be alert for flash floods.
- On open water: Get to land and find shelter immediately.
- Anywhere you feel your hair stand on end: Squat low to the ground on the balls of your feet. Place your ears over your head between your knees. Make yourself the smallest target possible and lessen your contact on the ground. DO NOT LIE FLAT on the ground.
Know the Terms
Familiarize yourself with these terms to help identify a thunderstorm hazard:Severe Thunderstorm Watch - Tells you when and where severe thunderstorms are likely to occur. Watch the sky and stay tuned to NOAA Weather Radio, commercial radio or television for information.
Severe Thunderstorm Warning - Issued when severe weather has been reported by spotters or indicated by radar. Warnings indicate imminent danger to life and property to those in the path of the storm.
During Thunderstorms or Lightning Storms
If thunderstorm and lightning are occurring in your area, you should:- Use your battery-operated NOAA Weather Radio for updates from local officials.
- Avoid contact with corded phones and devices including those plugged into electric for recharging. You can use cordless and wireless phones not connected to wall outlets.
- Don’t go near electrical equipment or cords. Unplug appliances and other electrical items such as computers. Turn off air conditioners. Power surges from lightning can cause serious damage.
- Stay away from the plumbing. Don’t wash your hands, take a shower, wash dishes or do the laundry. Plumbing and bathroom fixtures can conduct electricity.
- Stay away from windows and doors. Stay off porches.
- Do not lie on concrete floors. Don’t lean against concrete walls.
- Avoid natural lightning rods such as a tall, isolated tree in an open area.
- Try to stay away from hilltops, open fields, the beach or a boat on the water.
- Take shelter in a sturdy building. Avoid isolated sheds or other small structures in open areas.
- Don’t touch anything metal—tractors, farm equipment, motorcycles, golf carts, golf clubs and bicycles.
- If you are driving, try to safely exit the roadway and park. Stay in the vehicle and turn on the emergency flashers until the heavy rain ends. Try not to touch metal or other surfaces that conduct electricity in and outside the vehicle.
After a Thunderstorm or Lightning Strike
If lightning strikes you or someone you know, call 9-1-1 for medical help as soon as possible. Check the items listed below when you try to give aid to a victim of lightning:
- Breathing - if breathing has stopped, begin mouth-to-mouth resuscitation.
- Heartbeat - if the heart has stopped, give CPR.
- Pulse - if the victim has a pulse and is breathing, look for other possible injuries. Check for burns where the lightning came into and left the body. Be alert for nervous system damage, broken bones and loss of hearing and eyesight.
- Never drive through a flooded roadway. Turn around, don’t drown!
- Stay away from storm-damaged areas to keep from putting yourself at risk from the effects of bad thunderstorms.
- Keep listening to a NOAA Weather Radio or local radio and television stations for news and orders, as right to use roads or some parts of the area(s) may be blocked.
- Help people who may need special assistance, such as infants, children and the elderly or those with access or functional needs.
- Stay away from downed power lines. Report these lines quickly to the power company.
- Watch your animals closely. Keep them under your direct control.
Additional Resources
Want to learn more about thunderstorms, lightning and hail? Visit these sites to learn about the science behind these systems and how to be prepared:
- National Weather Service: Lightning Safety
- NOAA: Severe Thunderstorms
- NOAA: Severe Weather 101: Lightning
- Ready.gov: Lightning Safety
- ReadyNC.org: Thunderstorms & Lightning
Listen to Local Officials
In any emergency, always listen to the orders given by local emergency management officials.