HOW LIGHTNING HURTS US A lightning strike in a crowded stadium is hazardous out to roughly 50 feet from the strike point, with one or two fatalities and dozens of injuries. People are occasionally injured 100 feet away from a strike. LIGHTNING This is roughly equivalent to the kill radius and injury radius of a hand grenade. The mechanisms that hurt us are the millions of volts WHEN THUNDER ROARS RISK of electricity, the heat, and the thunderous blast from the rapidly GO INDOORS! CAMPERS FOR www.lightningsafety.noaa.gov expanding air. Ground current occurs with each strike. You can minimize your BACKCOUNTRY exposure to ground current by keeping your feet close together, especially avoiding lying flat on the ground. Ground current con- FRONTCOUNTRY LIGHTNING AND tributes to half of lightning fatalities (Fig. 1). This is the primary HOW LIGHTNING KILLS MANAGEMENT mechanism where we can easily reduce lightning risks. RISK MANAGEMENT DIRECT CONTACT STRIKES No place outside is safe from lightning. Frontcountry includes outdoor Side flashjumps from tall objects like trees when they are struck by UPWARD LEADERS settings that are within a 30-minute walk of modern buildings or HIKERS lightning, so don’t seek shelter near tall trees, other tall objects, or vehicles. This is where most lightning injuries occur because this is tall vertical surfaces. where people spend more time outdoors. Contact is from touching long conductors like railings, cables, and fences. Conduct a web search for dead cow lightning to see TAKE THESE SIMPLE PRECAUTIONS TO STAY MUCH SAFER FROM GROUND CURRENT morbid images of contact and sideflash. SIDE FLASH THE LIGHTNING HAZARD: Upward leaders emanate from high ground and tall objects when Get in a modern, enclosed building or a metal-topped vehicle if you downward leaders approach the ground: even if they don’t connect hear thunder. Look up “Faraday cage” to see why this is so with a downward leader, they can be fatal. helpful and why the vehicle needs a metal roof to protect you. Direct strikes cause about 3-5 percent of lightning fatalities. Avoid Avoid open shelters (like gazebos) and tall trees. high places and open ground to decrease risk of a direct strike. Fig 2. The frequencies of the primary lightning fatality mechanisms. Time your visits to high-risk areas with local weather patterns, so The explosive force of lightning can cause blunt trauma resulting you aren’t in a high-risk area at a high-risk time. in fractures or soft tissue injuries. FIRST AID FOR LIGHTNING VICTIMS We should primarily focus our efforts on avoiding ground current and side flash. The mechanisms that hurt us are electricity, First Aid heat, and the air blast. These cause many different kinds of neurological problems, burns, and trauma. vvv TREATMENT PRINCIPLES vvv Scene Safety: Avoid further injuries. It may be safer to wait for the storm to pass before treating victims in extremely hazardous locations. If this cow has 800kV at Basic Life Support: Be prepared to provide rescue breathing. 10 the front feet and 700kV at 9 the back feet, the 100kV Triage: Unlike normal triage protocols, attend first to those who are 8 difference drives electrons in cardiac or respiratory arrest without obvious lethal injury. 7 volts in one leg, across the torso, WEBSITES ABOUT LIGHTNING 6 of Assessment: All patients require a complete body survey and careful and out the other legs. 5 evaluation for head, spinal, long bone, or cardiac injuries. Assess National Weather Service Lightning Safety: www.lightningsafety.noaa.gov 4 thousands peripheral pulses, and sensory and motor status. Check the skin for of 3 NOLS Backcountry Lightning Risk Management: www.nols.edu/lightning small hidden burns. 2 Medical Aspects of Lightning: www.uic.edu/labs/lightninginjury 1 hundreds John Gookin 2012 Monitor for cardiovascular, respiratory, and neurological problems. Lightning Safety for Boaters: www.wrh.noaa.gov/vef/boatersafety.php#lightning Fig 1. Ground current causes about half of all lightning injuries. Evacuate anyone obviously injured by lightning. Be alert for lingering Youtube keywords for waiting for the storm to pass: (use wireless devices) A difference in voltage drives current through us. In this simplified issues that need further evaluation and treatment. Survivors could be lightning strike tree, car, or plane; Faraday cage; lightning on the lawn illustration the cow has a 100,000-volt differential, one farmer has a 50,000-volt differential, and the other farmer has her feet together so disoriented or confused. Their decision-making ability (including judg- her voltage difference is minimal. ment, direction finding, and planning) could be dangerously impaired. a build- v.6Mar2012 any a edge E you. an the on of TO L edge. metal- to are that you the light- of many This stand- reduce Gookin and conduct vertical gap, get the 3 out the extremely long Standing ). seek OSSIB a modern to John during conductors. 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IN in a a water. 4 upward riskier overall HAZARDS lightning GET STRIKING the move significantly reduce the effects of ground current. If yousignificantly reduce the effects have Fig. it. Crouch or sit to slightly reduce the effects of side flash it. Crouch or sit to slightly reduce the effects and M buildings. Boaters before of SAFER IS to your 4. 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