Lightning is one of the most underrated severe weather hazards, killing about the same number of people as tornadoes and more than hurricanes. Lightning kills about 50 people in the United States and about 2,000 people worldwide each year, injuring hundreds more. Lightning can occur anywhere there is a thunderstorm, with the most frequent strikes in July.

An estimated 25 million cloud-to-ground lightning flashes occur in the United States each year. While the National Oceanic and Atmospheric Administration’s National Weather Service issues severe thunderstorm watches and warnings for storms that produce damaging winds or hail, warnings are not always issued for lightning.

Lightning is a rapid discharge of electrical energy in the atmosphere; the rapid heating and cooling of the air creates a shock wave that results in a clap of thunder. During a thunderstorm, winds cause the various precipitation particles to collide, causing small ice crystals to lose electrons while larger particles of soft hail gain electrons.

Upward winds redistribute these particles and their charges. The soft hail causes a negative charge near the middle and lower part of the cloud, causing a positive charge to build up on the ground. When the difference between the negative charge in the cloud and the positive charge on the ground becomes large, the negative charge moves toward the ground, creating a conductive path in a zigzag shape as it jumps through segments in the air. When the negative charge connects with the ground’s positive charge, the charged current surges through the jagged path, creating a visible flash of lightning. Danger results from the millions of volts of electricity, the heat and the thunderous blast from the rapidly expanding air.

Five types of lightning strikes can harm people. Ground current occurs with each strike and contributes to half of all lightning fatalities. The current hits an object and spreads out through the ground; to avoid a ground strike, it helps to keep your feet together. A side flash jumps from tall objects like trees when they are struck; avoid seeking shelter under trees or tall objects. Conduction, responsible for most indoor lightning injuries, occurs when touching metal such as railings, cables and fences. Lightning can travel long distances through wires and metals. Direct strikes cause 3 to 5 percent of lightning fatalities; avoid high places and open ground to decrease risk. Streamers discharge when lightning strikes are nearby. Although not as common as other types of fatal incidents, victims caught in streamers are at risk for death or injury.

All thunderstorms produce lightning and are dangerous. Lightning often strikes outside the area of heavy rain, as far as 10 miles from rainfall. Many lightning deaths occur ahead of storms or after they have passed. Do not be fooled by blue skies; if you hear thunder, lightning is close enough to pose a threat.

While a small percentage of lightning strike victims die, many survivors must live with serious lifelong pain and neurological disabilities. After being struck, people are often confused and do not know what occurred. Although a survivor may suffer burns or fractures (from a fall), the greatest concern is the effect on the heart and nervous system.

A victim may experience difficulty with mental processes and multitasking, short-term memory loss, forgetfulness, distractibility, personality changes, irritability and depression. Physical effects can be long-term and include intense headaches, body pain, fatigue, difficulty sleeping, impaired eyesight, ear ringing, ruptured eardrums, hearing loss, loss of consciousness, severe electric shock, seizures, paralysis, burns to the skin, damage to internal organs and tissues, and trauma. Other longterm effects include cataracts, abnormal gait, joint dysfunction, muscle spasms and dry eyes.

To avoid a lightning threat, have a safety plan in mind. Identify a safe place and how long it takes to get there. Before going outdoors, check the forecast for thunderstorms; consider postponing activities to avoid a dangerous situation. Monitor the weather for signs of a developing thunderstorm such as darkening skies, increasing winds or lightning flashes.

If you hear thunder, even a distant rumble, immediately move to safety. Fully enclosed buildings with wiring and plumbing provide the best protection. Sheds, picnic shelters, tents and covered porches do not protect you. If a sturdy building is not nearby, get into a hard-topped metal vehicle and close the windows. Stay inside until 30 minutes after the last rumble of thunder.

Do not use a corded phone except in an emergency; cordless phones and cellphones are safe to use in a thunderstorm. Keep away from electrical equipment and wiring. Water pipes conduct electricity, so do not take a bath or shower or use other plumbing during a storm.

If someone near you is struck by lightning, act fast. It is safe to touch the victim. Cardiac arrest is the immediate cause of death for those who die from lightning strikes. Some deaths can be prevented if the victim receives immediate and proper first aid. Call for help. Call 911. Do not delay CPR if the person is unresponsive or not breathing. Use an automatic external defibrillator if available. If possible, move the victim to a safer place. Lightning can strike twice; do not become a victim.

A portable, battery-powered, tone-alert NOAA Weather All Hazards Radio enables you to monitor forecasts for changing weather conditions and severe thunderstorm watches or warnings. A free app for NOAA also is available for Android phones, iPhones or iPads.

The content of this article is for informational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition.