Don’t be fooled by the words to a song. Thunder—and therefore, lightning—doesn’t only happen when it’s raining.
Lightning can strike well beyond the rain-producing part of a storm, or even from a storm that produces no rain at all. Perhaps that’s why a pilot who lands just ahead of approaching weather may have to wait a while to have the fuel tanks topped off for tomorrow’s return flight.
Pilots aren’t the only airport-community members whose vulnerability to thunderstorm hazards concerns the FAA and airport operators. Line staff spend much of their time exposed to the elements, and the weather observations you study as a student pilot to help you remain well clear of convective activity also help determine when airport-ramp operations should be scaled back for safety.
“Lightning safety procedures and decision support information vary significantly at US airports,” the agency’s Weather Research Division said in an email to AOPA. “However, what these procedures have in common is that they make use of lightning information (or proxies thereof) to close the ramp and get workers inside if there is lightning within a critical safety radius of their location.”
The division suggests that airports use a critical safety radius of five miles around critical airport infrastructure, adding that “anything smaller than this radius may significantly increase the safety risk.” (Do you recall the minimum distance for a plot to circumnavigate a severe thunderstorm? See page 12-22 of the Pilot’s Handbook of Aeronautical Knowledge.)
The weather researchers recommend “at least a 10 minute waiting period after the last lightning event within the critical radius” before resuming operations.
You are likely familiar with abbreviations that differentiate lightning types in weather observations, such as IC (in-cloud), and CC or CG (cloud-to-cloud and cloud-to-ground) lightning. The FAA suggests that airports base their precautions on “total lightning,” because “a cloud-to-ground lightning stroke can occur whenever electric discharges are happening.”
In other words, not only when it’s raining.
Getting back to that pilot impatiently waiting for a top-off as a front approaches, he might be less antsy knowing that FAA weather experts suggest that airports use a second, larger safety radius “to provide a heads-up on approaching thunderstorms or to implement initial precautionary procedures (such as disconnecting wired headset communications for pushback or stopping refueling of aircraft, for example).”
Lightning is a hazard for all airport-community members. Knowing the hazards helps everyone stay safe.