Anvil clouds, also known as cumulonimbus, are storm clouds. These storm clouds were rather small, compared to the usual. As a storm that passed by Fargo to the west, missing Fargo, while heading southeast, I decided to get a time 4K lapse shot. At 30x real time, you can easily see the clouds passing by and even building up. All photos used ISO 200, f/4, 1/4000 second exposure at 12 mm with a 0.75 dynamic range exponent.