Space weather events from the Sun are increasing in frequency as we head towards the solar maximum in 2013. Things won't slow down until 2-4 years past maximum, so expect these types of events to be frequent over the next several years. Satellite owners, operators, and insurers will be most affected, but other industries such as the airlines, high-precision GPS users, and the electric utilities will also be on alert for major solar storms. Satellites directly feel the effects of energetic particles during a space weather event, and can suffer permanent damage. A part of our atmosphere called the ionosphere becomes severely disturbed after a solar storm, sometimes enough to cut out radio communication and interfere with GPS signals.
One issue on everyone's mind is the space weather threat to the electric power grid. A scenario where electric power is unavailable over a wide geographic area for an extended period of time makes people understandably anxious. This recent storm was nowhere near energetic enough to cause widespread damage. The coronal mass ejection started off at a very fast clip, approximately 2300 km/s upon leaving the Sun, which could have triggered a moderate to strong storm when it hit the Earth's atmosphere. But, we had no way of knowing how strong until it arrived, because the key component for energy transfer (magnetic field orientation) can only be measured very close to Earth (by the ACE satellite at the L1 position).The magnetic field of the coronal mass ejection was not in an orientation favorable for a strong storm (the most favorable orientation is opposite polarity of Earth's), and it turned out to be mild-to-moderate.
Space weather forecasting took a major step forward last year with the release of the WSA-ENLIL model. The model has predicted the arrival time of the last two major CME events to within an hour, which is a fantastic achievement. The next step in forecasting will be the prediction of the magnetic field strength and orientation upon arrival. Hopefully in the next several years the scientific community will have reached this forecasting milestone. Then we will be much better prepared for stormy weather from the Sun. For now, we have to watch and wait until it arrives to know how extreme the storm will, or will not, be.
*Blog photo is from NASA/Solar Dynamics Observatory