NOAA 2000-081
Contact: Barbara McGehan


A major solar flare occurred beginning on Thanksgiving evening, November 23 at 10:02 p.m. MST (24/0502 UT), with a second happening ten hours later on November 24 at 8:13 a.m. MST (24/1513 UT), according to NOAA's Space Environment Center in Boulder, Colo. Forecasters say that solar activity is likely to continue at moderate to high levels for the next several days.

As a result of this activity, a geomagnetic storm is expected to reach Earth on the evening of Saturday, November 25 or Sunday, November 26. "A drastic increase in the solar wind, or a shock wave, impacts the Earth's magnetic field, and typically, signifies the onset of the geomagnetic storm," forecaster Bill Murtagh said. Forecasters expect perhaps as many as four shock waves arriving in a 24-hour period this weekend. Geomagnetic storms travel at a rate of 1-3 million miles per hour.

Strong geomagnetic storms can cause satellites to experience surface charging and orientation problems and power systems can also be affected. Such storms can also interfere with high frequency radio communications. The initial solar flares already caused radio blackouts on the sunlit side of the Earth for about an hour.

Using NOAA's Space Weather Scales, the geomagnetic storm is predicted to be a strong storm (G 3), with the possibility that the storm may reach higher levels as the event progresses. "The rapid-fire sequence of events is unlike anything we've seen thus far, during this solar cycle," said Murtagh. According to forecaster Larry Combs, the danger lies in the duration of the storms. "We've had several flares and Coronal Mass Ejections (CMEs) in the past 36 hours, and if that continues, the constant bombardment of the Earth by the enhanced solar wind, could affect power systems and satellites."

The flares that produced these storms were categorized by forecasters as
X-2 events, X being the highest category of flares possible. The flares occurred in the north central area of the sun, which is expected to continue to be visible for the next seven days. There is, therefore, a distinct possibility of more activity occurring. "The region that produced these flares continues to grow and increase in complexity," Murtagh said. "In fact, it's almost doubled in size since yesterday."

The solar wind and particles produced as a result of these flares can produce Auroral Borealis, or northern lights as far down as Illinois and Oregon (typically 50 degrees geomagnetic latitude.)

NOAA's Space Environment Center is the nation's official source of space weather alerts and warnings and continually monitors and forecasts Earth's space environment.

For the latest information on solar storms and their progress go to: Click on "Space Weather Now."