Sometimes a trip doesn’t necessarily turn out the way you’d imagined, and then suddenly it all becomes worth it, whether it’s finding the perfect location or witnessing something unique. In yesterday’s case, it was witnessing a massive airglow display that included gravity waves emanating from the large thunderstorm complex that hit the Front Range last night (tennis ball-sized hail was reported at Red Rocks, and sent 9 to the hospital). Last time I witnessed this was from Independence Pass, while that thunderstorm dumped tennis-ball sized hail on Fort Collins, 165 miles from me.
While the lightning last night seemed quite distant, I could see the flashes from 185 miles away. Airglow is not generally easily seen with the naked eye, as humans have poor color perception at low light levels. Last night’s display, however, was easily visible! The red colors looked like dark bands in the sky, while the green was quite a bit brighter, and it seemed like I could just barely make out a greenish glow. As in the time-lapse below, I could see the radiating ‘arms’ moving around over the course of a couple of minutes, and the experience was much like witnessing a weak aurora display.
While airglow is quite common (see my post linked above for details), gravity waves are a bit less common, and are often associated with large atmospheric disturbances, which create an analog to ‘ripples on a pond’; that is, the atmosphere being disturbed and trying to balance itself out via bouyancy effects (wind waves on the ocean are similar). You can see this in the time-lapse video below.
(NOTE: Click the ‘Watch on YouTube’ below to see a higher-quality version; not sure why the embedded video is so compressed, probably YT wanting me to give them money…)