Prepare for Thunderstorm
Thunderstorms and lightning are among nature’s most dazzling weather phenomena. When dark storm clouds loom, and bolts of lightning streak across the sky, it can be captivating to watch. They are also among the most common and dangerous weather events, as about 300 people are injured and 80 people are killed every year in the United States due to lightning, according to the Centers for Disease Control and Prevention.
Lightning isn’t the only potential danger during a thunderstorm ”“ strong winds, flash flooding and hail can also accompany these storms. Tornadoes also are possible during severe thunderstorms and may form quickly, so play close attention to weather alerts during any storm.
Though spring in the U.S. is usually the busiest season for severe thunderstorms, they can occur in any season throughout the year.
- Warm, humid conditions offer the most favorable environment for thunderstorms to develop.
- Most deaths and injuries from lightning happen to people who have been caught outdoors in a storm in the afternoon and evening during the summer months.
- Though thunderstorms often bring heavy rainfall, lightning can occur far away from areas of heavy rain.
- If a severe thunderstorm watch or warning has not been issued, that does not mean that a storm isn’t dangerous – thunderstorms that aren’t designated “severe” still can be accompanied by lightning and hail.
- Equate thunder with lightning, even if lightning is not visible where you are. If you can hear thunder, you are close enough to a storm to be struck by lightning.
When Thunderstorms Are Likely
If you find yourself outdoors or in an area where thunderstorms are in the forecast or about to happen, follow these precautions:
- Postpone outdoor activities, and go indoors if you’re outside.
- Go indoors if you’re outside, preferably inside a home or building. Hard top cars offer shelter as well, but avoid convertibles. Although you may be injured if lightning strikes your car, you are much safer inside it than outside.
- Remember the “30-30″ rule: After seeing lightning outside, go indoors if you cannot count to 30 before hearing thunder. Stay inside for 30 minutes after hearing the last clap of thunder.
- Remove dead or rotting trees and branches that could fall or be blown around and cause injury or damage during a thunderstorm.
Family Preparedness Checklist
- Remove dead or rotting trees that could fall on your house or property if struck by lightning.
- Move inside your house or garage anything on your property that could become flying debris.
- Unplug any appliances or electronic equipment.
- Inventory all valuables in the home with pictures or video. Note the approximate value of each item and date of purchase.
- Make sure important documents, such as an insurance policy or mortgage papers, are stored in a safe-deposit or safe box.
- Read and understand your insurance policy, especially disclosures.
- Examine your homeowners’ coverage, as well as auto policies.
- Be sure you have adequate coverage and deductibles reasonable for your needs.
- If you have expensive or specialty items (e.g. jewelry, furs, silverware, cameras, collectibles, etc.), speak with your agent about broader coverage, as limits do apply under a homeowners’ policy.
- Sign up for The Weather Channel’s severe weather mobile alerts.
- Listen to NOAA Weather Radio for important updates.
- Consider buying a whole-house surge protector. Whole-house surge protection can protect against lightning strikes or damaged power lines that could cause a fire.
- Protect mementos in waterproof containers and/or take the items with you if you evacuate.
- Take care of your pets. Doghouses aren’t lightning-safe, and dogs that are tied to trees or other tall objects can also be hit by lightning.
What is a thunderstorm? What’s a severe thunderstorm?
- Preceded by a dark sky and sometimes a greenish light, and often accompanied by dark, low-lying clouds, thunderstorms are most common in the spring and summer months across much of the U.S. They may be fast-moving or they may move very slowly, seeming to hover over one location for an extended period of time.
- Thunderstorms usually produce brief periods of heavy rain, typically between 30 minutes to an hour. They can last much longer than this, however, depending on the severity.
- Roughly 10 percent of thunderstorms are classified as “severe thunderstorms,” which means that they produce hail at least 3/4 inch in diameter and have winds that reach speeds of 58 mph or higher. Any thunderstorm that produces a tornado is classified as a severe thunderstorm.
During the Storm
When you notice darkening clouds in the sky accompanied with sudden wind shifts, a thunderstorm may be approaching. If local authorities have issued a watch or warning, heed their instructions on what to do and whether you need to take cover.
When thunderstorms are likely, postpone outdoor activities and avoid going outdoors if at all possible. If you are caught outdoors in a thunderstorm, follow these tips to stay safe until the storm passes:
- If you are in an open area, find a low place such as a ravine or valley. Be alert for flash floods.
- If you are in a forested area, find shelter in a low area under a thick growth of small trees, if possible.
- If you are on open water, get to land immediately and seek shelter.
- If you are in a car, keep the windows closed.
- If you are outdoors and feel your hair stand on end (an indication that lightning is about to strike), do not lie flat on the ground, as your fully-extended body will provide a larger surface to conduct electricity. Instead, squat low to the ground and place your hands over your ears and your head between your knees. The goal is to make you the smallest target possible and minimize contact with the ground.
- Stay away from anything made of metal ”“ bicycles, golf clubs, golf carts, motorcycles, tractors and farm equipment.
- Stay away from natural lightning rods, such as a tall tree in an open field, and avoid hilltops,the beach or boats on open water.
In addition to heavy rains and the threat of lightning, hail can pose a big danger during a thunderstorm. Hail can be as small as the size of a pea, or as large as a softball. Because it falls from the sky, it can reach extremely high speeds as it barrels toward earth and damage anything in its path ”“ cars, windows and especially plants and agricultural crops.
If you see or hear hail hitting the ground during a thunderstorm, take it as an unmistakable sign that you need to remain inside if you’re already indoors, or find shelter quickly if you’re outdoors. A few facts about hail:
- Though hail rarely causes fatalities, more than 20 people are injured by falling hail each year in the United States.
- Hail size is measured by National Weather Service Doppler radar, which estimates the size of hail according to its diameter. Sizes range from pea-size (1/4 inch), to quarter size (1 inch) and golf-ball size (1 3/4 inches), all the way up to softball-size (4 1/2 inches). Hail larger than quarter-size (1 inch in diameter) is considered severe.
- The larger the thunderstorm, the greater the chance for larger hail to be produced – so stay alert if you notice especially large thunderstorm clouds developing in your area.
- The majority of hail damage each year occurs to agricultural crops, as the area of the U.S. most at risk for large hail lies in the western Great Plains states. This 625-square-mile-wide area sees an average of 7 to 9 days with hail each year.
If you’re indoors when thunderstorms are imminent or occurring in your area, stay inside and follow these tips to secure your home and property:
- Shutter windows and secure outside doors. Also, close your window blinds, shades or curtains, and keep a safe distance from them.
- Secure any objects outside your home that could blow away or cause damage.
- Stay away from faucets, sinks, showers and bathtubs. Plumbing and bathroom fixtures can conduct electricity.
- Avoid using a corded (landline) telephone during a thunderstorm, for the same reason. Cellular/mobile phones are safe to use.
- Unplug electrical appliances such as televisions, computers and corded phones, and turn off air conditioners. Power surges that occur as the result of lightning can cause severe damage to plugged-in electronics and appliances.
- Keep pets inside, on a leash or in a crate or carrier.
- Make sure you have a battery-powered radio or NOAA Weather Radio so you can receive weather alerts and storm updates if you lose power.
Know Your Terms
- A severe thunderstorm watch is issued when conditions are conducive to the development of severe thunderstorms in and around the watch area, and indicates when a severe thunderstorm is likely to occur.
- A severe thunderstorm warning is issued when a severe thunderstorm has been observed by spotters or indicated on radar. Warnings indicate that a severe thunderstorm is occurring or imminent in the warning area, and is a danger to life and property in the path of the storm.
Source: Centers for Disease Control and Prevention