Hurricane Igor, unchained, in NASA satellite images

While its intensity has dropped slightly, massive Hurricane Igor remains a powerful Category Three storm, with maximum sustained wind speeds of 105 knots (115 miles per hour) as it continues on a projected collision course with Bermuda this weekend. The storm is bringing large swells to the Lesser Antilles, Virgin Islands, Puerto Rico, Hispaniola, the Bahamas and the east coast of the United States.

Igor is one of three hurricanes currently active in the Atlantic/Caribbean Sea/Gulf of Mexico - only the ninth time in recorded history that three hurricanes were active in this region at the same time. The other current storms are Julia in the central Atlantic, a Category One storm with maximum sustained winds of 75 knots (85 miles per hour), and Karl, which made landfall today in southeastern Mexico and is currently a Category One storm with maximum sustained winds of 95 knots (110 miles per hour).

All three storms were captured in infrared in these Sept. 17, 2010 images by the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The AIRS data create accurate 3-D maps of atmospheric temperature, water vapor and clouds, data that are useful to hurricane forecasters. The images show the temperature of the storms' cloud tops or the surface of Earth in cloud-free regions. The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.