NASA's Earth Observatory has posted before and after satellite images of the mid-Atlantic region showing the extent of the power outages after the June 29th storm. The land hurricane - technically called a "derecho", or "long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms" - left over 4 million people without power for several days. The images are from the Suomi National Polar-orbiting Partnership satellite, which takes measurements using visible and infrared spectra.
June 28 (before the storm):
June 30 (after):
Larger files along with a nifty comparison slider tool are available over at NASA's Earth Observatory site.