Dr. Tom: How do I prevent getting caught in a lightning storm? What if a member of my party is struck by lightning?  

If you can hear thunder, you are close enough to a storm to be struck by lightning. The absence of clouds overhead or rain does not mean you are safe. The safest place during a thunderstorm is in a modern building or a metal-roofed vehicle. Open shelters, tents, and lean-tos offer no protection from lightning.

The best approach to staying safe from lightning is monitoring weather forecasts and avoiding or quickly passing through high-risk environments like summits, exposed ridges, boats or open water, windward sides of mountains, and tall objects like isolated trees.

But sometimes, despite our best planning, a storm catches us off-guard. As soon you hear thunder, head as quickly as possible toward safer terrain, like a gully, a low, rolling hill, or a dry ravine.

Most lightning injuries occur from ground currents or side flashes. A ground current spreads through the ground after striking nearby. A side flash is a current that jumps from a tall object, like a tree that has been struck, to a nearby person. Once lightning is close, spread out the individuals in your group at least 50 feet apart but within sight of each other. This will decrease the likelihood of lightning striking multiple victims. Avoid standing too close to relatively tall trees, in wide open ground, or near long ground conductors like metal fences. Get into the “lightning position”: Place your feet together; crouch (but don’t sit), hunched over, on a foam mat or backpack; close your eyes to protect them from lightning’s brightness; and remain in that position until the storm has passed.

If a person is struck by lightning, the electrical shock can cause immediate cardiac or respiratory arrest. Initiate CPR on a victim as soon as possible, with use of an automated external defibrillator, or AED, if one is available. (Each of AMC’s White Mountain huts, Galehead and Carter Notch huts, has an AED.)

If a victim is breathing immediately after being struck, they have a high chance of survival, though may have other injuries. The concussive force of a lightning strike can throw a victim, causing trauma such as broken bones and head injury. Burns are also common as rain turns to steam on the skin and jewelry becomes superheated. Perform a full assessment to find more significant injuries and treat with basic first aid. Most lightning strike victims should leave the backcountry immediately, though a person’s injuries—such as temporary paralysis known as keraunoparalysis—may necessitate a carry-out evacuation.