Presentation on theme: "Lightning Safety Oklahoma Dept of Corrections | Staff & Organizational Development."— Presentation transcript:
Lightning Safety Oklahoma Dept of Corrections | Staff & Organizational Development
Course Information Data source: National Oceanic & Atmospheric Administration (NOAA), U.S. Dept. of Commerce. Website: http://www.noaa.govhttp://www.noaa.gov Photography: All photos, including title background, are courtesy of NOAA. Course design: Lynne Presley, Oklahoma Dept. of Corrections, Staff and Organizational Development Unit, email@example.com firstname.lastname@example.org Course published October 12, 2005. Oracle SAFI39000. Course credit: One hour (assuming all links are followed).
Course Objectives At the end of this course, students will be able to: 1.Understand the different ways that cloud to ground lightning can kill people. 2.Name at least 2 physical injuries that a lightning bolt can cause. 3.Calculate a storm's distance by using the "Flash to Bang" method. 4.Understand indoors and outdoors safety precautions to avoid being struck by lightning.
Introduction Did you know that lightning is the second-leading weather killer in the U.S.? (Floods are number one.) Lightning is more deadly than tornadoes or hurricanes. According to the NOAA, lightning strikes in the U.S. kill over 70 people and injure hundreds more each year. According to the NOAA: Approximately 25 million cloud to ground lightning strikes occur in the U.S. each year. The air within a lightning strike can reach 50,000 degrees Fahrenheit. Lightning can heat its path five times hotter than the surface of the sun One ground lightning strike can generate between 100 million and 1 billion volts of electricity.
How Lightning is Formed ++ Lightning is caused by the attraction between positive and negative charges in the atmosphere, resulting in the buildup and discharge of electrical energy. This rapid heating and cooling of the air produces the shock wave that results in thunder. During a storm, raindrops can acquire extra electrons, which are negatively charged. These surplus electrons seek out a positive charge from the ground. As they flow from the clouds, they knock other electrons free, creating a conductive path. This path follows a zigzag shape that jumps between randomly distributed clumps of charged particles in the air. When the two charges connect, current surges through that jagged path, creating the lightning bolt. (NOAA)
How Lightning is Formed, cont'd. Lightning flashes don't always strike the ground. They can occur within a cloud, or from cloud to cloud. NOAA
Lightning Damage Cloud to ground lightning can injure and kill people in different ways. For instance, lightning can strike and hit a person directly. Lightning can also branch off to a person from another object, such as a tree, pole, or other tall object. Also, lightning may travel through power and phone lines and plumbing pipes to a person who is in contact with an electric appliance, telephone, or plumbing fixture. Lightning striking the Eiffel Tower, June 3, 1902, at 9:20 P.M. NOAA
Lightning Damage, cont'd. These cows were killed when lightning struck the fence, and the current traveled along the fence killing the cows. Photo: NOAA/Ruth Lyon-Bateman
Physical Injuries Lightning strikes can produce a variety of physical injuries and disabilities, including: Cardiac arrest Brain damage and nervous system injuries Pain and bodily damage from being thrown by the strike Impaired thinking and mental confusion Burns Death On average, 20% of lightning strike victims die, and 70% suffer serious long-term effects.
Lightning Warning Signs High winds, rainfall, and a darkening cloud cover are the warning signs for possible cloud-to-ground lightning strikes. Things to remember: If you can hear thunder, lightning is close enough to strike your location. Lightning can strike miles away from any rainfall. Lightning can also travel sideways for many miles. If you hear thunder, look for cover. How Long Can a Lightning Bolt Be? Recent research from Vaisala- GAI's LDAR and LDAR II lightning detection networks show that lightning can travel 60 miles or more. The longest bolt they have seen to date was 118 miles long in the Dallas-Ft. Worth, Texas area. Since 3-D lightning measurements are relatively new, however, scientists are learning more every day and these numbers may change. Source: National Severe Storms Laboratory, NOAA
Storm Proximity It's not uncommon to see a flash of lightning, then hear the thunder some seconds later. It's possible to estimate how close the storm is by using the "Flash to Bang" method. According to NOAA, it's very simple: 1.Once you see a lightning flash, start counting the seconds until you hear the thunder. 2. Divide the number of seconds by 5 to get the distance in miles. Example: If thunder is heard:The lightning is: 10 seconds after a flash2 miles away 10 seconds divided by 5 = 2 miles Remember: If the time between a lightning flash and the sound of thunder is 30 seconds or less, seek shelter immediately!
Safety Precautions - Inside There is no way to guarantee that you won't be hit by lightning. However, taking safety precautions can reduce the risk. A house or substantial building offers the best protection from lightning. Why? Because they have pipes and wires going into the earth, which grounds the structures. Be sure to follow these safety tips from NOAA while in a house or building during the thunderstorm: Avoid contact with corded telephones, electrical equipment, and cords. Avoid contact with plumbing. Do not wash your hands, do laundry, wash dishes, or take a shower or bath. Stay away from windows, doors, and porches. Do not lie on concrete floors, and do not lean against concrete walls (the concrete may contain wire mesh, which can conduct electricity).
Safety Precautions – Outdoors Remember that NO OUSIDE LOCATION IS SAFE DURING A THUNDERSTORM! However, if you are outdoors when a thunderstorm occurs, and you can't find shelter in a building, follow these NOAA safety guidelines to avoid the most hazardous locations: Stay away from partially-open outdoor shelters, such as car ports, picnic shelters, tents, open garages, and covered patios. Some vehicles are safer than others. Safer vehicles include those with hard tops. Unsafe vehicles include convertibles, golf carts, motorcycles, bicycles, boats, and other vehicles with soft or no tops.
Learn More About It Many people believe that a vehicle's rubber tires protect them from being hit by lightning, so it doesn't matter if the vehicle has a top or not. Untrue! Actually, the metal frame and roof of a vehicle provide protection by diverting the electrical current away from the people inside. This is why vehicles with soft tops and convertibles are less safe than vehicles with metal tops – the current can't be diverted along the top.
Safety Precautions – Outdoors There are other precautions you can take if you are outdoors when a thunderstorm occurs, and you can't find shelter in a building: Do NOT seek shelter under tall isolated trees or poles. Lightning typically strikes the tallest object. Stay away from metal objects such as fences, wires and poles. This isolated pole is a magnet for lightning!
Warning Signs People sometimes receive a few seconds of warning before being struck by lightning. For instance, the following events have been reported: Hair standing up Tingling skin Light metal objects start to vibrate Seeing a corona discharge (electrical spark) Hearing a crackling sound If you experience any of these warning signs, and cannot seek inside shelter, assume the position shown on the next slide.
Safety Precautions – Outdoors If lightning is in the immediate area, and there is no safe location nearby, get into the "lightning crouch" position. Crouch down, but DO NOT lay down. Bend your knees down while keeping your feet together. (NOAA) The "Lightning Crouch" position. NOAA NOTE: If you're with a group, everyone should spread out so there are several body lengths between each person. Once spread out, assume the position shown in the picture to the right.
First Aid Being struck by lightning doesn't mean automatic death. People who are struck by lightning don't carry a charge – it's safe to touch them and provide medical treatment. Call 911 immediately, and conduct a basic first-aid assessment, focusing on breathing and pulse. Begin CPR as necessary while you wait for medical assistance to arrive. (NOAA)
Course Review: Question 1of 10 1. The air within a lightning strike can reach 50,000 degrees Fahrenheit. Click here for correct answer Answer: True Click here for next question
2. Rapid heating and cooling of air during a storm produces a shock wave that results in _________. Answer: Thunder Click here for correct answer Click here for next question Course Review: Question 2 of 10
3. Lightning flashes always strike the ground. Answer: False. Lightning can also flash within a cloud, and from cloud to cloud. Click here for correct answer Click here for next question Course Review: Question 3 of 10
4. Lightning can hit a tree, then travel to a person. Answer: True Click here for correct answer Click here for next question Course Review: Question 4 of 10
5. Being hit by lightning "jolts" the brain and improves brain function. Answer: False. Being hit by lightning can cause brain damage, impaired thinking, and mental confusion. Click here for correct answer Click here for next question Course Review: Question 5 of 10
6. High winds, __________, and a darkening cloud cover are warning signs of a possible cloud to ground lightning strike. Answer: Rainfall Click here for correct answer Click here for next question Course Review: Question 6 of 10
7. The "Flash to Bang" method helps to identify how close a storm is. Use the method to solve this problem: If thunder is heard 5 seconds after a lightning flash is observed, how far away is the storm? Answer: 1 mile. To calculate the distance, remember this formula: # of seconds divided by 5 = distance in miles Click here for correct answer Click here for next question Course Review: Question 7 of 10
8. Taking an indoors shower or bath during a thunderstorm does not increase a person's chance of being struck by lightning. Answer: False. Remember that electrical current can travel through plumbing pipes and hit you. Click here for correct answer Click here for next question Course Review: Question 8 of 10
9. Why does a house or other substantial building offer protection from being struck by lightning? Answer: Because most houses and buildings have pipes and wires going into the earth, which "grounds" them and guides electrical currents into the earth. Click here for correct answer Click here for next question Course Review: Question 9 of 10
10. It's a good idea to seek shelter during a thunderstorm under the tallest tree you can find. Answer: False. Lightning typically strikes the tallest object in an area. Click here for correct answer Course Review: Question 10 of 10
Learn More About It Want to learn more about lightning storms? Visit these sites: http://www.noaa.com/lightning.html The National Oceanic & Atmospheric Administration's "Lightning" web site. http://www.nssl.noaa.gov/researchitems/lightning.shtml The National Severe Storms Laboratory's "Lightning" web site.
Conclusion Obviously, we want to avoid being struck by lightning. We can improve our chances by following the safety precautions in this course. Stay alert, and stay safe!