Hurricane Katrina

Storm History

Katrina began as a slow-moving easterly wave of low pressure in the trade wind belt near the west coast of Africa. The mass of rain clouds traveled across the Atlantic Ocean, becoming Tropical Depression 12 on August 23, 2005. The system intensified overnight to Tropical Storm Katrina (39 mi./hr., or 63 km/hr.) east of the Bahamas. Rapid strengthening followed as the system passed over 82 °F (28 °C) water. These storms feed on the latent heat of condensation, and warmer water provides more energy for the storm.

Hurricane warnings were posted along the Southern Florida coast. On August 25, Katrina reached 74 mi./hr. (119 km/hr.) and Category 1 status on the Saffir-Simpson Hurricane Damage Potential Scale. At 5 p.m., Katrina made landfall near North Miami Beach with sustained winds of 80 mi./hr. (128 km/hr.), causing flooding and damage and taking 14 human lives. By morning, Katrina had reached the Gulf of Mexico and moved westward over the warm water of the Loop Current. Sea surface temperatures reached 92 °F (33 °C), feeding rapid intensification.

By August 27, the system shifted course to the northwest and then north, provoking warnings for the Gulf Coast from Western Florida to Louisiana. Category 5 status was achieved on August 28, when winds crossed the 155-mi./hr. (250 km/hr.) mark, only to increase to 175 mi./hr. (280 km/hr.), with a central pressure of 902 mb (millibars) (26.61 in./hg [inches per hectogram]) later that day; normal sea-level pressure is 1,013.2 mb.

The governor of Louisiana declared a state of emergency for her state on August 26, followed by President George W. Bush's major disaster declaration on the afternoon of August 28. Evacuation efforts were underway by the morning of August 28. Estimates place the number of people who were evacuated at nearly 1 million, with 374,000 of these listed at shelters in other states. The critical problem was that 120,000 residents of the New Orleans area did not have [Page 1494]personal automobiles and had to rely on public transportation.

A buoy 50 mi. southeast from the mouth of the Mississippi River measured a wave height of 55 feet (16.8 meters) on the morning of August 29—a record for the National Data Buoy Center. Landfall occurred at 6:10 a.m. CDT (central daylight time) in Plaquemines Parish between the Mississippi River mouth and Grand Isle. Katrina slowed to a Category 3 with sustained winds up to 130 mi./hr. (210 km/hr.). By 8:00 a.m., Katrina was 40 mi. southeast of New Orleans, shifting slightly to the east; then, by 10:00 a.m., it made a second landfall along the Louisiana-Mississippi border. The lethal front-right quadrant of the storm was hitting the Mississippi Gulf Coast, while easterly winds north of the eye wall were pushing the waters of Lake Pontchartrain into New Orleans. The storm surge and winds obliterated many towns, with the damage extending east into coastal Alabama. Sixty oil spills, totaling 4 million gallons, occurred as facilities along the coast broke and more than 100 oil-drilling platforms were destroyed.

...