explanation
This aurora was a bit of a surprise. For starters, on this Friday morning in August 2002, no intense auroral activity [ http://sprg.ssl.berkeley.edu/~cyclopi/lesson1.html ] was expected at all. Possibly more surprising, however, the aurora [ http://science.nasa.gov/spaceweather/aurora/gallery_01aug02.html ] appeared to show an usual structure of green rays [ http://www.baa-aurora.fsnet.co.uk/theaurora.htm ] from some locations. In the above image [ http://science.nasa.gov/spaceweather/aurora/images/01aug02/Anderson1.jpg ], captured from North Dakota [ http://www.state.nd.us ], USA [ http://www.cia.gov/cia/publications/factbook/geos/us.html ], a picket fence of green rays stretches toward the horizon. Mirroring the green [ http://antwrp.gsfc.nasa.gov/apod/ap000519.html ] rays is a red [ http://antwrp.gsfc.nasa.gov/apod/ap020115.html ] band, somewhat rare in its own right. Lights from the cities of Bismarck [ http://www.bismarck.org/ ] and Mandan are visible near the horizon. Large sunspot groups indicate that activity from an active Sun [ http://antwrp.gsfc.nasa.gov/apod/ap020801.html ] is relatively likely, possibly causing other streams [ http://antwrp.gsfc.nasa.gov/apod/ap020101.html ] of energetic particles to cascade onto the Earth and so causing more auroras [ http://antwrp.gsfc.nasa.gov/apod/ap020121.html ].
Explanation
false