It was a sunny and calm day for the most part at Emerald Lake in Yoho NP, Canada, but once sunset began a hail storm broke out. Then the fog and clouds rolled in, thunder erupted and the lightning flashed up in the mountains. I was just shooting long exposure shots as the low clouds swept over the lake, when I got lucky and caught a lightning strike in the distance. I didn't stay out there too much longer after this since the storm really cranked things up.

Nikon D750, Nikkor 28-300mm, ND filter, tripod

Edited in Lightroom. Just minor adjustments; fixing lens distortion, shadows up and highlights down.