14:41 Mon May 11, 2020
Something's Abuzz...Lightning Safety!
For this week’s observer post, I wanted to continue the theme of this week’s virtual classroom topic – lightning and lightning safety. This topic warrants some extra attention because of how dangerous lightning is, and how crucial it is to understand what to do (and what not to do) when lightning is nearby. Weather observers will go outside into some pretty crazy conditions to do our hourly readings, but we will never go out if there is a thunderstorm near the summit due to the danger of lightning.
Lightning is an immense electrical discharge ranging from 100 million to 1 billion volts delivered over a few milliseconds. Within just a few millionths of a second, it heats the surrounding air to about 50,000⁰F – about five times hotter than the surface of the sun. Though the majority of people struck by lightning survive, they may suffer significant and lifelong disability. Fortunately, there are a number of things you can do to stay safe during a thunderstorm.
Lightning bolts over Wildcat B.
Lightning can strike 10-12 miles from its parent thunderstorm – and strikes have even been documented more than 25 miles away. Since thunder is only heard for about 10 miles, you should seek a safe shelter as soon as you hear it, and wait about 30 minutes after the last rumble before you head out. A safe shelter is an enclosed building with plumbing and electricity or a metal-topped vehicle with the windows rolled up. A building’s plumbing and electrical wiring are excellent conductors, so they will conduct the electricity to the ground if the structure itself is struck. Small and less robust buildings or those with open sides, like dugouts, porches or sheds, or vehicles like convertibles or golf carts do not offer adequate protection.
Lightning to the southeast, with the Stage Office and Tip Top House in the foreground.
Once you’re inside, there are still steps to take to be sure you’re safe. After all, the plumbing and electrical wiring can also conduct the charge to you! So, while you can use a cell phone that is not plugged in, anything plugged into electrical outlets can conduct the charge. Surge protectors do not provide adequate protection from the magnitude of surge from a lightning strike, so while you can protect electronics by unplugging them before a storm, it’s best not to risk yourself once there’s lightning in the area. Also keep clear of water: Electricity travels well in water, whether you are swimming outside or taking a bath inside, or even doing dishes or laundry.
If you can’t get indoors, there are still some things you can do to lower your risk. Electricity takes the “easiest” path as it travels, and the shorter paths are easier. So, it’s safer to be lower (and not to be on hills, mountaintops, and ridges where you are higher up and the path to you is shorter). Keep clear of things that conduct electricity like water, and do not take cover under large trees, rocky outcroppings, or metal structures. Being near a tall object (like under a tree) can cause a “side splash” whereby lightning hits the tree, then jumps to the person next to it for the rest of the journey to the ground.
An impressive thunderstorm to the northwest over Vermont.
Lightning makes a thunderstorm an awe-inspiring event to watch, but it is also extremely dangerous. We take lightning safety seriously at the Observatory and you should too. For more information on the creation of lightning and lightning safety, check out Ian’s excellent presentation on our Facebook page or on our Virtual Classroom page at mountwashington.org/classroom
AJ Grimes, Weather Observer