On Wednesday, September 9, 2020 at 5:36:24 AM UTC+1, Mike Reid wrote:
Sounds like you encountered St. Elmo's Fire, which is quite common when flying through dry precipitation like snow or ice crystals. If it had been dark, you would have seen the sparks to go along with the clicking sound.

https://www.youtube.com/watch?v=7huPWGX-yz0

Mike
Yes indeed, flying a glider (or any other aircraft for that matter) under a charged rain cloud can result in an electrical discharge. Often known as point discharge, it might be heard as clicks (from sparks) or as a buzzing on your radio. More intense discharges produce the glow of St. Elmo's fire.. In my Discus 2, it would make the hairs on my leg near the release cable stand on end! While not dangerous (except perhaps to sensitive avionics), I always saw it as a hint to go fly somewhere else.

Most lightning discharges to aircraft are fairly minor ones triggered by the plane itself flying through cloud or rain. It's rare for an aircraft in flight to connect with a more energetic ground flash, although that is exactly what happened to the famous English glider incident mentioned in an earlier post. That glider ended up forming part of the path for a rather energetic positive ground flash and expanding air or water vapor from the discharge inside the wings blew them apart rather dramatically. If you avoid flying in cloud or the rain directly under a thundercloud, the chances of a lightning strike are small.

Mike