This image was taken on 11/10 on CU Boulder East Campus facing West at 5:28pm. The atmosphere is stable and the cloud type is stratus

Clouds Second: Red Altostratus Clouds

                  This image was taken for the Cloud Second assignment. This cloud formation was captured on November 11th, 2025 at 5:28pm on CU Boulder East Campus, facing west towards the flatirons. These clouds were particularly interesting to me because of the cloud’s texture, color, and size.

In this image, the cloud type was Altostratus Undulatus. The wind speeds were low for most of the day, and there was no approaching front or inclement weather. The rest of the sky to the east had cloud coverage similar to the cloud photographed, while to the west it was clear. From the skew-T diagram, the atmosphere is stable and the cloud height would be expected to be about 4 km. Both of these support that the cloud is altostratus undulatus. Altostratus undulatus clouds form when there is a stable atmosphere, moist clouds, and wind shear. The defining aspect of the altostratus undulatus is the wind shear that creates the ripples in the cloud. The wind shear was likely produced by the flatirons. The mountains create lee waves, where the wind speed increases as altitude increases.

                  This photo was taken on an iPhone 14 main digital camera at f1.5, ISO 640, and a 1.1s exposure. The image size is 4032x 3024 pixels. The image was cropped horizontally to remove a building and vertically to remove the parking lot. The image had its contrast slightly increased, and the color curve had the yellows and greens reduced to take color out of the foreground.