Lightning strike, tornado (cyclone), hurricane (typhoon), flood, earthquake, tidal wave (tsunami), landslide (mudslide), volcano, and snow avalanche

Lightning strike

Lightning strikes the earth at least 100 times per second during an estimated 3000 thunderstorms per day. Fortunately, the odds of being struck by lightning aren’t very great. Approximately 50 persons per year are victims of fatal strikes in the United States, but the number has been declining because of better education and awareness. The wise traveler respects thunderstorms and always seeks shelter during a lightning storm. If you hear thunder or see lightning, then seek shelter.

Lightning is the direct-current electrical discharge associated with a thunderstorm; it releases an initial charge (the vast majority of which travels from ground [positive] to cloud [negative]) of average 30 million volts to neutralize a potential difference (within a hundredth to a ten-thousandth of a second) of 200 million to a billion volts. A lightning flash can be made up of multiple (up to 30) strokes, which causes lightning to seem to flicker. Each stroke lasts less than 500 milliseconds. The diameter of the main stroke is 2 ½ to 3 inches (6 to 8 cm); the temperature has been estimated to be anywhere from 14,432°F to 90,032°F (8000°C to 50,000°C—four times as hot as the surface of the sun). Within milliseconds, the temperature falls to 3632°F to 5432°F (2000°C to 3000°C).

Thunder, which is always present with lightning, is attributed to the nearly explosive expansion of air heated and ionized by the stroke of lightning. To estimate the approximate distance in miles from your location to the lightning strike, time the difference in seconds between the flash of light and the onset of the thunder and divide by five. For instance, a lightning strike 1 mile away causes sound to reach you in 5 seconds. A “crack” is relatively close by, while a “rumble” indicates multiple strikes of varying distances, with the “high notes” filtered out by the air. Note that thunder is seldom heard if it is generated more than 10 miles (16 km) away.

Lightning can injure a person in many ways:

• 1.

  Direct hit, which most often occurs in the open.

• 2.

  Splash, which occurs when lightning hits another object (tree, fence, building). The current seeks the path of least resistance and might jump to a human. Splashes might occur from person to person.

• 3.

  Contact, when a person is holding on to a conductive material that is hit or splashed by lightning.

• 4.

  Step (stride) voltage (or ground current), when lightning hits the ground or an object nearby. The current spreads like waves in a pond.

• 5.

  Ground current.

• 6.

  Surface arcing.

• 7.

  Upward streamer current.

• 8.

  Blunt injury, which occurs from the victim’s own muscle contractions and/or from the explosive force of the shock wave produced by the lightning strike. These can combine to cause the victim to be thrown, sometimes a considerable distance.

When lightning strikes a person directly, splashes at them from a tree or building, or is conducted along the ground, it usually largely flows around the outside of the body (flashover phenomenon), which causes a unique constellation of signs and symptoms. The victim is frequently thrown, clothes might be burned or torn (“exploded” off by the instantaneous conversion of sweat to steam), metallic objects (such as belt buckles) might be heated, and shoes removed. The victim often undergoes severe muscle contractions—sufficient to dislocate limbs. In most cases, the person struck is confused and rendered temporarily blind and/or deaf. In some cases, there are linear (1 ½ to 2 inches [1.3 to 5 cm] wide, following areas of heavy sweat concentration), “feathered” (fernlike; keraunographism; Lichtenberg’s flowers—cutaneous imprints from electron showers that track over the skin) ( Fig. 245 , A), or “sunburst” patterns of punctate burns over the skin (see Fig. 245 , B), loss of consciousness, ruptured eardrums, and inability to breathe. Occasionally, the victim ceases breathing and suffers cardiac arrest. Seizures or direct brain damage might occur. Eye injuries occur in half of victims.

A victim struck by lightning might not remember the flash or thunder, or even recognize that they have been hit. The confusion, muscle aches, body tingling, and amnesia can last for days. With a more severe case, the skin might be mottled, the legs and/or arms might be paralyzed, and it might be difficult to locate a pulse in the radial (wrist) artery (see page 28), because the muscles in the wall of the artery are in spasm. First-, second-, or third-degree skin burns might be present. Broken bones are not uncommon.

If a person is found confused, burned, or collapsed in the vicinity of a thunderstorm, consider the possibility that they were struck by lightning. The victim is not “electrified” or “charged”—you will not be jolted or stunned if you touch them.

• 1.

  Maintain the airway and assist breathing (see page 18). Continue to perform artificial respiration and cardiopulmonary resuscitation (CPR) (see page 28) until advanced help can be obtained. Victims of lightning strike might have paralysis of the breathing mechanism for a period of up to 30 minutes, and then make a remarkable recovery. A seemingly lifeless individual might be saved if you breathe for them promptly after the injury. Do not assume that dilated or nonreactive (to light—see page 74) pupils are a sign of death, because they might represent direct injury to the eye(s).

• 2.

  Assume that the victim has been thrown a considerable distance. Protect the cervical spine (see page 33).

• 3.

  Examine the victim for any other injuries and treat accordingly.

• 4.

  Transport the victim to a hospital.

• 5.

  If you are in the vicinity of a thunderstorm, seek shelter for the victim and yourself. Lightning can strike twice in the same place!

Lightning avoidance and how to seek safety

• 1.

  If you hear thunder, it’s best to curtail activities and seek shelter from lightning. Know the weather patterns for your area. Don’t travel in times of high thunderstorm risk. Avoid being outdoors during or before a (threatening) thunderstorm. Carry a radio to monitor weather reports. Lightning can lash out from many miles in front of a storm cloud, in seemingly clear weather. If you calculate (see earlier) that a nearby lightning strike is within 3 miles (5 km) of your location, anticipate that the next strike will be in your immediate area. Don’t resume activities outdoors for at least 30 minutes after the lightning is seen and the last thunder heard.

• 2.

  If a storm enters your area, immediately seek shelter. Enter a hard-roofed auto or large building. Tents and convertible autos offer essentially no protection from lightning. Rubber tires are not protective. Metal sheds are dangerous because of the risk of side splashes. Indoors, stay away from windows, open doors, fireplaces, and large metal fixtures. Inside a building, avoid plumbing fixtures, telephones, and other appliances attached by metal to the outside of the building.

• 3.

  Don’t carry a lightning rod, such as a fishing pole or golf club. Rubber-soled shoes and raincoats don’t provide protection. Don’t touch long conductors, such as wet ropes, metal fences, and handrails. Avoid tall objects, such as ski lifts and power lines. Avoid being near boat masts or flagpoles. Don’t seek refuge near power lines or tall metal structures. Avoid being near metal pipes and fences. If you’re in a boat, try to get out of the water. If you’re swimming in the water, get out. Don’t stand near a metal boat. Get off bicycles, motorcycles, and golf carts.

• 4.

  Move off ridges and summits. Thunderstorms tend to occur in the afternoon, so attempt to summit early and be heading back down by noon. In the woods, avoid the tallest trees (stay at a distance from the nearest tree that’s at least equal to that tree’s height) or hilltops. Shelter yourself in a thick stand of smaller trees (e.g., saplings). Don’t shelter under an isolated tree. Avoid clearings—you become the tallest tree. If you are in a clearing, seek the lowest point, such as a valley or ravine. Don’t stay at or near the top of a peak or ridge. Avoid cave entrances. If you are out in the open and cannot find shelter, then put your feet together and try to stand on insulation, such as a foam hiking pad. Crouch down and try to put your chest against your thighs or knees, and keep your head low. This might be an uncomfortable position to hold but do your best. Never lie flat on the ground. Insulate yourself from ground current by crouching on a sleeping pad, backpack, jacket, or coiled rope.

• 5.

  Stay in your car and roll up the windows. The rubber tires are not protective. If it is a convertible, huddle on the ground at least 50 yards (46 m) from the vehicle.

• 6.

  If you are part of a group of people, spread the group out so that everyone isn’t struck by a single discharge.

• 7.

  If your hair stands on end, you hear high-pitched or crackling noises, or see a blue halo (St. Elmo’s fire) around objects, there is electrical activity near you that precedes a lightning strike. If you can’t get away from the area immediately, crouch down on the balls of your feet and keep your head down. Don’t touch the ground with your hands.

• 8.

  The StrikeAlert Personal Lightning Detector (Outdoor Technologies, Inc.) is the size and configuration of a pager and uses an audible warning and LED display to show the wearer how far away lightning is striking and if a storm is approaching or leaving. The StrikeAlert HD is larger and has additional features.

Tornado avoidance and how to seek safety

• 1.

  Be alert for a tornado if the weather conditions are rapidly changing, particularly if a stormy sky is dark gray or green and you see large hail or dark rotating clouds or hear a loud roaring noise. If you see revolving, funnel-shaped clouds, you’re in danger.

• 2.

  As soon as you note an approaching storm, seek shelter. If a storm shelter is available, use it. The best location is an underground cave or concrete structure. Otherwise, go to the lowest floor of a sturdy building. Don’t remain in a tent or camper. Mobile homes are not adequate protection.

• 3.

  If you are already indoors, go to a shelter area such as a storm cellar or basement; otherwise stay in the center of an interior room on the lowest level away from corners, windows, doors, and outside walls. Don’t open windows. Get under a sturdy table and protect your head and neck.

• 4.

  If a tornado is in your vicinity and you are caught outside in open country, hunker down or lie flat in a depression, ditch, culvert, or ravine. Cover your head with your arms and hands. Don’t get under an overpass or bridge—you’re safer in a low, flat location.

• 5.

  Don’t try to outrun a tornado. There is no way to predict when it will change direction. Flying debris is everywhere, and also be alert for flooding.