A solar wind stream hit Earth's magnetic field during the waning hours of Saturday, Feb. 18th. Although the stream was expected, the bright auroras it produced were not. Northern Lights spilled across the Canadian border into several US states including Wisconsin, Michigan, North Dakota, and Minnesota:

Travis Novitsky took this picture from Grand Portage, MN. "Last night, my girlfriend and I were just settling in to watch a movie when the auroras made a surprise appearance," he says. "A quick look out the back door of my house revealed that, yes indeed, the lights were out! We jumped in the truck and drove a few miles inland from Lake Superior. For the next hour and a half we were treated to a green glow peppered with dancing curtains of green, purple and red. It was a spectacular night."

In Fairbanks, Alaska, "the auroras were so bright they drew a crowd on my street," reports Brandon Lovett. At the Poker Flats Research Range outside of Fairbanks, researchers launched a suborbital rocket to investigate how auroras affect GPS systems. Lovett could see the rocket soaring into the heavens from more than 20 miles away.

This episode might have been amplified by the action of a co-rotating interaction region or "CIR." CIRs are transition zones between fast and slow solar wind streams. Solar wind plasma piles up in these regions, producing density gradients and shock waves that do a good job of sparking auroras. Local solar wind data suggest that Earth moved through a CIR around 1500 UT on Feb. 18th.

More Images:
From Dirk S.Miller of Rice Lake, Wisconsin; from Shawn Malone of Marquette, Michigan; from Matthew Moses of Solway Township, MN; from Brian Larmay of Beecher, Wisconsin; from Shawn Johnston of Fargo, North Dakota; from Aaron Peterson of AuTrain, Michigan; from Bryan Hansel of Grand Marais, MN; from Randy Halverson of Madison, Wisconsin; from Rob Harrington of McBain, MI.