Hello,
You heard correctly! This Friday (March 13, 2009) will be the 20th anniversary of the March 13, 1989 HydroQuebec blackout. On Thursday, March 9, 1989 scientists observed a solar flare. The next day, a large cloud of plasma erupting from the Sun was observed - I believe this was a coronal mass ejection (CME). When the CME reached the Earth, it interacted with our magnetosphere to produce a very powerful geomagnetic storm. The powerful current systems in the Earth's magnetosphere and ionosphere resulted in geomagnetically induced currents (GICs) in the power transmission lines which caused a transformer maintained by HydroQuebec to fail catastrophically. The failure of this transformer caused a blackout that affected 6 million people for over 9 hours.
Geomagnetic storms are dangerous, but not in the same way that hurricanes or tornadoes are dangerous. Geomagnetic storms can cause failures in the electrical power system, like the one in Canada in 1989. They can also cause communication and weather satellite failures, and pose a risk to astronauts in space. If I remember correctly, passengers and crew on trans-polar airplane flights can be exposed to about the same level of radiation as a chest X-ray during strong geomagnetic storms and solar flares. This is why the National Oceanic and Atmospheric Administration (NOAA, the same people who forecast "Earth" weather like blizzards and hurricanes) now have a Space Weather Prediction Center. Knowing when to expect solar flares, CMEs, and geomagnetic storms can help the operators of satellites and electrical power systems plan ahead so these systems that are vital to our nation's infrastructure can keep on operating as normal. Space weather predictions also allow airlines to adjust their flight plans to avoid trans-polar routes and the astronauts to take precautions to avoid trouble from the geomagnetic storm.
Here are a few places where you can learn more:
NOAA Space Weather Prediction Center - http://www.swpc.noaa.gov/
http://www.agu.org/sci_soc/eiskappenman.html
http://www.solarstorms.org/
http://www.publicsafety.g...02/ta02-001-eng.aspx
http://spaceweather.com/
http://www.windows.ucar.e...eather/blackout.html