Auroras above LaCrosse, Wisconsin, at 4 o'clock in the morning local time on Nov A solar storm rattled Earth's outer defenses early this morning, generating colorful northern lights as far south as Wisconsin and Michigan. The space cloud is expected to clear early Friday.
The storm, called a coronal mass ejection (CME) was generated along with a medium-class solar flare Nov. 18. The cloud of charged particles arrived at about 3:30 a.m. ET (0830 GMT).
Despite being associated with a moderate flare, the CME was aimed squarely at Earth and generated "strong to extreme" geomagnetic storming, said Paal Brekke, deputy project scientist for the Sun-watching SOHO spacecraft.
Extreme space storms can threaten satellites and power grids. No reports of damage have resulted so far from this bout of space weather.
More flares, including possible extreme events, are possible in the next few days. The current storm emanated from Sunspot 484. Sunspots 486 and 488 have just rotated into view on the left limb of the Sun. The trio was responsible for a string of 10 major flares in a two-week period during late October and early November.
All three spots are capable of producing intense eruptions this week, forecasters said.
The chance of a major solar flare is 25 percent each day through Saturday, according to NOAA's Space Environment Center.
The current storm had a southward magnetic orientation this morning. That is opposite the orientation of Earth's protective magnetic field. This opposing configuration brews stronger geomagnetic storms, scientists say.
"This event illustrates very well that even a modest flare and a modest halo CME can cause very strong geomagnetic storms here at Earth if it has a south magnetic component," Brekke said.
Northern lights, called auroras, could continue at far northern latitudes overnight. The colorful displays are created when charged particles, accelerated locally by the interaction of the storm with Earth's magnetic field, excite molecules of oxygen and nitrogen in Earth's atmosphere.
Update: As of 7 a.m. ET Friday, Nov. 21, the storm was subsiding. Thursday evening, auroras were seen as far south as Maryland, Virginia, and possibly even Florida. No new flares have yet erupted, but NOAA forecasters said the potential for severe flares exists for the next two weeks.
advertisement
