Background
- Three experienced divers engaged in an underwater line laying operation in a river during a perceived break between thunderstorms.
- Lightning struck the dive site while divers were at a depth of 20 ffw (6 mfw).
- Divers experienced an electric discharge through their limbs while holding conductive metal materials.
Reported Incident
A team of three experienced divers engaged in an underwater line laying operation in a river during a perceived break between thunderstorms. In the middle of the operation, lightning struck the dive site while the divers were at a depth of 20 ffw (6 mfw). At the time of the lightning strike, the divers were utilizing heavy metal disk brakes and a lift bag to anchor the line. The divers reported experiencing electrical discharges through their limbs while holding the metal disk brakes.
Recognizing the potential for injury, the divers immediately ceased activities and surfaced before calling Divers Alert Network (DAN) for guidance on lightning strike protocols. The divers were advised to seek medical attention and undergo physical evaluation.
After a thorough medical evaluation, the divers were released from the hospital with no reported injuries. The doctor’s assessment stated no immediate adverse effects from the lightning strike.
Review
Considering the operation required utilizing conductive equipment and occurred during a perceived break between thunderstorms, the divers’ decision to complete the line laying operation was ill-advised. To avoid being caught out in a storm, the divers should have better familiarized themselves with local weather patterns and reviewed the forecast as part of their dive planning.
Even if there is a blue sky overhead, lightning may still be a hazard if storm clouds are in the area. It is not uncommon for lightning to strike several miles from a storm; in rare cases, “bolts from the blue” have struck the ground or water as far away as 10 to 15 miles from storm clouds, possibly even farther.
Electrical charges generally dissipate at depths 20-30 feet below the surface; however, it is possible the conductive materials used during the operation led the divers to experience the electrical discharge through their limbs.
The divers’ actions to contact Divers Alert Network (DAN) after the incident to seek guidance and medical attention demonstrated effective communication to addressing any possible health risks incurred from the lightning strike.
Recommendations
Avoid diving or being in the water during a storm. If caught in the middle of a storm while scuba diving, divers should exit the water as quickly as possible and seek shelter. If a diver is unable to surface safely and seek shelter, the diver should let go of any metal objects and submerge to a depth of 20 to 30 feet in accordance with safe diving guidelines until the storm passes and the diver is able to exit the water safely. Once exiting the water safely, it is recommended that the diver seek medical attention immediately, as necessary.