Thunderstorm with some ground strikes coming over — BIG dynamic range!

Warning — big dynamic range!

A gradual approach of this May thunderstorm in Exeter, UK city centre, culminating in an apocalyptic-sounding ground strike, and then… nothing much! The rainfall that came over sounded only moderately heavy, though with a scattering of hailstones for a short while.

For a few days the UK Met Office had been showing a quite good thunderstorm likelihood for Exeter from mid-morning to mid-afternoon on 9 May 2023, but then on the day the indications changed to just some mostly light showers — the thunderstorms now being expected elsewhere. So I didn't bother after all to set up my recorder on my bedroom window ledge — until, by late morning the thickening clouds were now beginning to look dark and thundery, and I was wondering… I set up the recorder just in case, but then realized that the breeze was enough to blow rain in over the recorder (as indeed forecast), and in the right direction to do so. So I took it down and closed the window, and got on with some work.

Then I heard the odd semi-distant rumble of thunder from a system that was passing-by rather than coming over. I returned the recorder to the bedroom window sill just in case, but that system was already moving away, and the recorder captured nothing worthwhile. But the Rain Alarm app on my phone showed another chunk of heavy to torrential shower coming up close behind, and Lightning Tracker, also on my phone, showed some strikes in that area. It looked as though the wind had dropped, too, so I left the recorder running, and captured about 56' of that particular storm.

Most of it wasn't overhead. It came in from WSW, and as so often happens when a storm does occur here, one arm of it was passing by to the SE, and the other arm passing by on the NE side, with mostly less intense precipitation and darkness here than on either side. A good proportion of the lightnings, even when distant, could be recognised as at least containing ground strikes, because of their sudden heavily explosive sounds. And as usually happens when a thunderstorm does get as close as it's going to, the lightning frequency dropped. Thus when it had got loud to a certain point there were only few further flashes, with big gaps.

After the first of those big gaps we get the two strongest strikes of all — the second of those being truly apocalyptic in sound if listened to at the indicated volume setting (see further below). There was a further strike with a rather similar sound to that biggest one, but it was one of the many casualties of city noises, and I had to cut it out. — And after that, just rain, and with a lot of city noise, so I cut all that out too. The original 56' of the recording got reduced to 29' in the process.

Advisory

Because of the big dynamic range, in order to hear most of the sound even at all, you need to listen at a volume setting of some 24 (yes, twenty-four) dB above a normal sensible setting. High-grade headphones strongly recommended!

An earlier thunderstorm (11 August 2019) developing as it approaches, seen from my living room window, with almost the same view as where this new recording was made.

Techie stuff:
The recorder was a Sony PCM-D100, with two nested Windcut custom furry windshields, and set up on a Velbon Mini tripod.

Post-recording processing was to apply EQ in Audacity to correct for the muffling effect of the windshields, plus correction for a low bass resonance in the particular window recess.

Please remember to give this recording a rating — Thank you!