Aurora Over Clouds . ... Credit Copyright: Dominic Cantin Explanation: Aurorae usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact air molecules high in the Earth's atmosphere . ... The lowest part of an aurora will typically occur at 100 kilometers up, while most clouds usually exist only below about 10 kilometers. ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...