UPDATE (January 25, 2012): I've posted the interview with John Kappenman below. He puts the magnitude of this storm in perspective.
On Sunday evening, the sun unleashed a bright solar flare. Along with the flare came a coronal mass ejection, a blast of charged particles that began colliding with the earth's magnetosphere today.
The current storm is expected to be rather moderate, reaching just 2 or 3 on the G-scale, a measure of solar storm intensity that ranges from 1, the least severe, to a maximum of 5. Airlines have diverted flights that were scheduled for polar routes, because the geomagnetic activity can interfere with the high frequency communications systems they use to stay connected to ground control stations.
But as John Kappenman explains in our February cover story, a severe solar storm could wreak havoc on power grids, oil and gas pipelines, and communications networks. Nuclear power plants appear to be particularly vulnerable. The last time we had a truly powerful storm was 1921, and our utter dependence on electrical infrastructure makes us much more vulnerable today. Kappenman notes that Sunday's event wasn't well positioned to cause a direct-hit on earth; had a flare erupted in the same location late last week, the impact here would have been worse.
I'll be chatting with Kappenman later today, and he'll provide an update on today's storm. We'll also discuss what lessons can be learned from the 1989 geomagnetic storm that knocked out power in all of Quebec. Check back here at 3:00 PM EST for more.