Arctic Circle Aurora on March 16-17, 2013
What caused these magnificent Northern Lights?
Sunspot region 1692 was the source of a significant long duration M1.1 solar flare occurring at 06:58 UTC on March 15, 2013 - associated with a large full halo coronal mass ejection (CME). The solar storm reached the Earth near 10:00 PM Alaskan time on March 16 (06:00 UTC on March 17) and the CME arrival triggered a 12 hour-long geomagnetic storm producing colorful Northern Lights visible as far South as the Northern tier of the United States.
Canon 5D MKII with EF 50mm f/1.2L and EF 24mm f/1.4L II lenses