Irene formed as a tropical storm east of the Leeward Islands on August 20, 2011. By August 22, the storm had strengthened to a Category 1 hurricane. At 2:00 p.m. Atlantic Standard Time on August 22, the U.S. National Hurricane Center (NHC) reported that Irene had maximum sustained winds of 80 miles (130 kilometers) per hour, with higher gusts. The storm was located about 150 miles (240 kilometers) west-northwest of San Juan, Puerto Rico.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image at 11:20 a.m. local time (15:20 UTC) on August 22. Storm clouds cover part of the Dominican Republic, and all of Puerto Rico.
As of August 22, Irene had cut power to more than a million residents of Puerto Rico, according to ABC News. The Miami Herald reported that heavy rains had pushed at least five rivers over their banks on the island. Citing continuing rains, downed power lines, and potential landslides, the Puerto Rico governor urged residents to stay indoors.
Moving westward to the island of Hispaniola, Irene menaced the Dominican Republic and Haiti. The storm’s worst winds and rains remained north of the island, reducing the threat of deadly flooding, according to news reports. Nevertheless, authorities worried about approximately 600,000 Haitians still living in Port Au Prince tent cities after the 2010 earthquake.
The NHC reported that a hurricane warning was in effect for the north coast of the Dominican Republic, the southeastern Bahamas, and the Turks and Caicos Islands. A hurricane watch was in effect for the north coast of Haiti. Irene was moving toward the west-northwest at roughly 12 miles (19 kilometers) per hour, and was expected to continue in that direction for the next day or two.
Five-day projections released by the NHC on August 22 showed Irene heading for the continental United States, potentially making landfall in Florida, Georgia, or the Carolinas.
NASA image courtesy Jeff Schmaltz, MODIS Rapid Response, NASA Goddard Space Flight Center. Caption by Michon Scott.