This is a "green flash" sunrise - a rare optical phenomenon that occurs in the few seconds after sunrise/sunset. It is usually seen over oceans where the horizon is flat and clear, but I was able to see this from Central Virginia (looking east at sunrise) due to exceptionally clear air and ~2000 ft of elevation in the Blue Ridge Mountains. This particular green flash lasted about 3-5 seconds just as the sun came up over the horizon, and was likely enhanced by distant clouds serving to distort the light (similar to iridescence). I had seen a green flash once before from this location, but this was my first time capturing it on camera.

Shot location: Afton Overlook on the Blue Ridge Parkway in Nelson County, VA.

Canon Rebel t3 with a Sigma 100-400 lens. 1/60s at f/6.3 and iso 100.

Slightly contrast and color enhanced in Adobe Lightroom. Significantly cropped to approximately 800mm equivalent