Some of the exposures are time lapse photos. I am not sure how long of a lapse they are but they are done quite well.
Lightning photography in general is pretty tough. I have tried it only once in my career, but it is something I would like to attempt again soon. The tricky part is having a good storm that has lightning which strikes the ground. Many of the Minnesota storms roll through late at night and only have cloud-to-cloud lightning. These types of pulses make for flashes of glowing cloud rarely a visible bolt of electricity.
My one dashed attempt at lightning photography took place while working for the newspaper. I had just gotten my photos in for the night and was on my way home when I noticed the electrical storm that was rolling into Red Wing. I decided to haul up to Memorial Park and see if I could get anything in the can. Now, I had never given much thought as to how one might execute good lightning photography. It quickly dawned on me that I needed a tripod and that time-lapse was the way to go. My reflexes, though not fast as they used to be, could never have caught up with the flash of a lightning bolt. My problem was that I did not have a tripod in my car. The next best thing was to set the camera on the roof of my car and attempt a remote trigger in order to prevent camera shake when pushing the button. I think I took seven photos but all I needed was two. This is the second frame I shot:

A lot of the flash was caught up in the cloud, but some of the actual bold is visible. I rushed back to the paper and got the photo to the editor in time for it to make the front page the next day. Though it was not uncommon for me to take on the responsibility of finding a feature for the next day's front page, this one was especially rewarding for me.