Cone Of Protection
If the issue of insulation generates sparks, then the “cone of protection” unleashes a firestorm of highly charged opinion. To visualize the cone, imagine the height of a pinnacle or tall tree, and use that height as a radius to create a circle around its base. The theory is that within the perimeter of this circle, you’re too far away from the tall object to be affected by “splash” or ground currents, yet not so far as to be an alternate target for a strike. Some sources say the object must exceed 100 feet in height for this theory to be effective.
The concept may have emerged from research into protecting structures with lightning rods, with the idea being that larger structures require taller, or multiple, lightning rods for protection. It’s also often used as a recommendation for boaters, but it’s important to note that masts or antennas can be grounded to conduct and dissipate a strike. A kayak or canoe does not have that option.
The folks at the National Outdoor Leadership School (NOLS), while warning that this is a very controversial topic, point out that at times, large topographic features have seemed to offer relative protection in the same way as tall artificial structures. Even so, there is no evidence that it works.
“I believe the cone of protection is a total fallacy that we should avoid mentioning ever again,” says Dr. Cooper, citing a study refuting the cone theory’s utility based on the burgeoning population of metal towers across the country. NOLS, meanwhile, continues to study the topic.
“Unfortunately we can’t do double-blind studies to see what works. My recommendations and those of NOLS are based on anecdotal experience,”
Dr. Johnson observes.
What to do?
So, the question remains: What can you do to stay lightning-safe in the backcountry? Your first and best option, all experts agree, is to stay clear of high-risk areas when thunderstorms are likely. In that respect, one weather pattern that rarely differs, regardless of region of the country, is that mountains in summer breed late-afternoon thunderstorms generally between the hours of 2 and 6 p.m., according to the NLSI. As the day winds on, avoid high ridges and mountaintops (especially those that hide your view of oncoming storms), exposed areas, and lakes. Or simply follow the “summer in the mountains” rule: up high by noon, down low by two.
It also helps to know the “flash to bang” method of calculating how long it’ll take an approaching storm to reach you. Simply count the number of seconds between the flash of lightning and the crash of thunder. Five seconds equals a mile. Keep in mind that a storm can advance 6 to 8 miles between lightning strokes, and that lightning strikes have been documented 10 miles in front of a storm. In other words, don’t assume you can ignore thunderclouds just because they’re way off in the distance. If you can still count seconds between flash and crash, you have time to get to a safer spot. Do it, then wait until 30 minutes after the storm passes to head out again.
The NLSI and the Lightning Safety Group recommend avoiding isolated trees, metal (pack frames, even), and small shelters during a thunderstorm. They also advise against touching dissimilar objects, like rock and ground or tree and ground. Seek out clumps of shrubs or trees of similar height. Tents offer no safety on open ground.
If you take all of the above-mentioned precautions, you’ll increase your odds of staying safe. But if your hair stands on end, metal objects or wet rocks hum, and you notice the smell of ozone or a bluish tinge of St. Elmo’s fire around boulders or a person, you’re being warned. The clouds and ground are negotiating a target for a lightning strike, and you don’t want to be it.
If you are ever caught without shelter in a thunderstorm, experts recommend crouching in the “lightning-safety position” with only your feet contacting an insulation material placed on the ground. The logic behind this position is that you’re lowering your height (and therefore propensity to attract lightning), as well as reducing your contact with the ground and your vulnerability to ground currents. Keep your feet together, and space people in your group at least 15 feet apart–NOLS recommends 30 feet–so that not everyone is hit. Cover your ears to minimize hearing damage from thunder shock waves.
Lightning-knowledgeable people use words like “capricious,” “random,” “unpredictable,” and “erratic” when describing the way the bolts behave. They also acknowledge that when you’re outdoors, there’s no absolutely safe place to be. You’ll be at risk regardless of your location. But we all accept a certain level of risk when venturing into the wilderness. The best thing to do is face up to the possibilities of what can go wrong, prepare as best you can with knowledge and information, stay aware of weather conditions, and if the worst-case scenario does unfold, head to safety.