“The time has come the Walrus said to talk of many things.”* He left lightning off his list. Had be been a sailor I don’t think he would have. There are plenty of tutorials on this electrifying subject. Many of which reveal it’s still not that well understood. But regionally speaking, you can see above there are some places you’d just rather not be when lightning season comes to call. The Worldwide Lightning Location Network is an interesting resource worth a look. This image, below, is just an exemplar of their offerings.
In these days of music players having displaced FM radio which displaced AM radio (yes you can still buy them), many fail to realize, an AM radio makes an excellent lightning canary. If you hear a snapping, popping crackle (use a frequency not being used for broadcast service) on the radio, consider that haze out there may be hiding something that requires your attention. While there will be some variability in loudness based on bolt strength, it is a pretty good bet, louder means closer. At night, though, AM “skip” can alert you to lightning literally thousands of miles away. But at night you have the flashes…oh, boy.
Purpose built detectors are available. Some purport to provide azimuth and range, and well they may. There is some debate as to whether some are worth the cost and complexity and can stand up to the marine environment. For us, AM crackle plus other weather information seems sufficient.
We have had two near misses from Zeus. Once in Florida in 1975, a bolt obliterated a day mark about 12 meters from us. The lights and triangles were disappeared and the battery box was burning when we looked up from our maximum cower position which we dove into when our hair stood away from our arms and heads. Then on the Chesapeake, 1982, a bolt-from-the-blue** hit a boat two away from us in our marina. We were acoustically and emotionally stunned, but nothing was damaged on our boat. Later that day we found the pieces and parts of the other boat’s instrument sensors and wind indicator laying on the dock. They were significantly modified by heat.
*If you haven’t read the “Walrus and The Carpenter” by Lewis Carroll, 1872, I commend it to you.
**A similar bolt from an even bluer sky hit a friend’s boat in Florida in 1973. It stopped his tiller-steering guest’s heart. It blew the depth-sounder transducer from the hull. Our friend kept up CPR on his guest while steering the sinking boat for the marina they had just left. The VHF was a crispy critter. As fate would have it, a cardiac surgeon and his nurse wife saw the boat get hit and turn sharply back to the marina. They called an ambulance. The inert, but now breathing, casualty was whisked to a hospital and recovered to bedevil us on the race course for years (when lightning weather was not extant). The boat sank at the dock. The water was shallow enough, docklines were able to keep it upright until the hole could be plugged and the boat refloated–also to bedevil us on the racecourse. The casualty eventually moved to New England; lightning incidence most certainly had something to do with it.