Why some thunderstorms produce excessive lightning

June 9, 2021: Michael Ward, 70, was playing golf in New Jersey when he was struck by lightning and killed.
June 12, 2021: A 15-year-old woman was struck by lightning while swimming in Tybee Island, Georgia.

Until June 9, we held a record for the last of the year the nation did so without recording a devastating death.

As one of the primary killers associated with thunderstorms, the death toll from lightning sometimes rivals that of tornadoes. In 2020, 17 Americans were killed by lightning.

On Saturday I was returning from Alabama to Savannah. From Emanuel County to Chatham County, I drove in and out of thunderstorms on I-16. Each produced excessive driving rain and lightning. My hands were holding the steering wheel so tightly that it hurt when I got home.

After posting the heartbreaking news of the teenager killed by lightning while swimming on Tybee Beach, many viewers asked me why these storms produced so much lightning. Well, there are three main reasons.

First, HIGH INSTABILITY RELEASE. When the instability is high, the stormy updrafts will be more intense. The stronger the updraft of the storm, the deeper the storm column will be. When the air rises in a thunderstorm, it cools. When the height of the thunderstorm is very high, the top of the thunderstorm cools down to very cold temperatures. This intense freezing freezing the top of the storm and this can be considered the anvil of the storm. The glaciation process produces a charge differential in the storm cloud. In cases where very rapid and intense glaciation occurs, lightning and thunder will be generated to a significant degree. All thunderstorms have ice in the upper parts of the storm. The speed at which the ice expands, the depth of the ice portion of the storm, and the speed at which precipitation moves through the cloud are important to the lightning process. There is still a lot of research to be done to fully understand this process.

Then, HIGH HUMIDITY CONTENT. Dew points of 60 degrees Fahrenheit or higher will bring significant humidity in a storm. Well, Saturday in Savannah we had dew points in the 70’s. Low humidity helps by increasing instability. This in turn leads to a stronger updraft as shown in the first reason above. An increase in humidity also means that more ice can be produced when the humidity begins to freeze in the updraft.

Finally, WIND SHEAR. Wind shear is the wind speed changing significantly with height and / or wind direction changing significantly with height. Wind shear allows a thunderstorm to last longer because it helps shift the updraft from the downdraft. These storms often present themselves as multicellular or supercellular storms. Wind shear also increases turbulence in a thunderstorm. This violent mixture of precipitation in the air could help improve load separation during a storm.

On Saturday we had all of these categories.

Lightning deaths do not tend to garner as much media attention as deaths from other disasters such as tornadoes or hurricanes, as the death toll, while tragic, is comparatively lower at individual events. But in 2018, only 10 Americans were killed by tornadoes, but 21 died from lightning.

Men are hit three to four times more often than women.

A long-term average of 41 people die from lightning strikes in the United States each year, but that number continues to decline thanks in part to increased awareness, safety campaigns, and increasing access to weather forecasts and alerts and warnings. .

But sometimes… an alert doesn’t come or it doesn’t come soon enough.

A typical lightning bolt measures about 300 million volts and 30,000 amps – enough to kill.

Most electric shocks spread horizontally rather than vertically. This is bad news for people who tend to float or swim on or near the surface.

Lightning current is likely to radiate through the surface.

Lightning doesn’t strike the ocean as much as it does land, but when it does, it spreads over the water, which acts as a conductor. It can hit nearby boats and shock fish near the surface.

For this reason, as soon as the sky darkens, I recommend that you pack your bags and go to a safe place.

Do not wait for the first thunderbolt or the first thunderclap. Download a reliable weather app and watch the radar. Many weather apps, including the free WSAV weather app, provide lightning data. You can also receive alerts when the lights are within 10 miles of your area.

If you are outside when a thunderstorm approaches… here is what to do.

To be aware
Check the weather forecast before participating in outdoor activities. If the forecast calls for thunderstorms, postpone your trip or activity, or make sure safe and adequate shelter is readily available.

Go inside
Remember the expression “When the thunder rumbles, come inside. “Find a closed, safe shelter when you hear thunder. Safe shelters include homes, offices, malls, and hard-top vehicles with the windows rolled up.

Seek shelter immediately even if caught in the open
If you are stuck in an open area, act quickly to find adequate shelter. The most important action is to remove yourself from danger. Crouching or getting low to the ground can reduce your chances of getting hit, but doesn’t keep you away from danger. If you are caught outside without a safe shelter nearby, the following actions may reduce your risk:

  • Immediately descend from elevated areas such as hills, mountain ridges or peaks.
  • Never lie down flat on the floor. Squat in a ball-like position with your head tucked back and hands over your ears so that you are low with minimal contact with the ground.
  • Never take shelter under a single tree.
  • Never use a cliff or rocky overhang for shelter.
  • Get out of ponds, lakes and other bodies of water immediately.
  • Stay away from electrically conductive objects (barbed wire fences, power lines, wind turbines, etc.).

If you are in a group during a thunderstorm, separate from each other. This will reduce the number of injuries if lightning strikes the ground.

Do not

Do not stay in vehicles, structures and open spaces
During a thunderstorm, avoid open vehicles such as convertibles, motorcycles, and golf carts. Be sure to avoid open structures such as porches, gazebos, baseball shelters, and arenas. And stay away from open spaces such as golf courses, parks, playgrounds, ponds, lakes, swimming pools and beaches.

Do not stay near large structures
Do NOT lie on concrete floors during a thunderstorm. Also, avoid leaning on concrete walls. Lightning can pass through any wire or metal bar on concrete walls or floors.

(sources: National Weather Center, NOAA, Washington Post, Lightning Stats, Professor Jeff Haby)

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