11:30 a.m.: The National Hurricane Center reports that the hurricane is "rapidly strengthening" as it crosses the Gulf of Mexico's very warm waters. In only a few hours, the storm's strongest winds have increased to about a hundred miles an hour (160 kilometers an hour).
During the day: Governors Kathleen Blanco of Louisiana and Haley Barbour of Mississippi declare states of emergency in their respective states.
- Hurricane Katrina: Complete Coverage
- Katrina Online: Strange Tales, Pleas for Help, Offers of Aid
- Photo Gallery: Pets, Hurricane Katrina's Other Victims
- Fishing "Shut Down," Oyster Beds Destroyed by Katrina
- Katrina's Stranded Pets Spur Massive Aid Effort
- Katrina Weakened, But Didn't Wipe Out, Invasive Rodents
11 p.m.: The National Hurricane Center predicts that Katrina will become a major hurricane by the time it reaches the central Gulf of Mexico. The eye of the storm is now about 460 miles (740 kilometers) southeast of the mouth of the Mississippi River in Louisiana.
SATURDAY, AUGUST 27
5 a.m.: Katrina's strongest winds have reached 115 miles an hour (185 kilometers an hour), making it a Category Three hurricane.
During the day: Hurricane-hunter aircraft fly into Hurricane Katrina to measure wind speed, barometric pressure, ocean surface temperature, and other data.
"It was certainly very strong and also was very large," Chris Landsea said later. Landsea, a meteorologist with the National Oceanic and Atmospheric Administration, was aboard a flight into Hurricane Katrina. "When we were flying into it Saturday, its circulation covered the entire Gulf of Mexico."
SUNDAY, AUGUST 28
2 a.m.: Hurricane Katrina's winds have increased to 145 miles an hour (235 kilometers an hour), making it a Category Four storm. The eye of the storm is about 310 miles (500 kilometers) south of the mouth of the Mississippi River.
9:30 a.m.: New Orleans Mayor Ray Nagin issues a mandatory evacuation order. Tens of thousands of New Orleans residents begin streaming out of the city.
"We're facing the storm most of us have feared," Nagin said. "This is going to be an unprecedented event." (See "News Video: Why New Orleans Is Vulnerable to Hurricanes").
11 a.m.: Hurricane Katrina has mushroomed into one of the most powerful hurricanes ever to form in the Atlantic. The storm's strongest winds are blowing at about 175 miles an hour (280 kilometers an hour), making it a Category Five storm. The center of the storm is about 225 miles (360 kilometers) from the mouth of the Mississippi River.
5 p.m.: The National Hurricane Center describes Katrina as a "potentially catastrophic" hurricane (See "News Video: Hurricane Katrina Animation").
"Some levees in the greater New Orleans area could be overtopped," the center warns. "Significant storm surge flooding will occur elsewhere along the central and northeastern Gulf of Mexico coast."
9:15 p.m.: A. J. Holloway, mayor of Biloxi, Mississippi, says his city is "getting some rain, a little wind, and some lightning and thunder" from Hurricane Katrina.
Holloway survived Hurricane Camille in August 1969, and he's worried that this hurricane will be as bad or worse than that catastrophic storm. He's also worried that many new residents of Biloxi have no idea what they may soon be facing.
"There's a lot of new people who moved into Biloxi with the advent of casino gambling who have never experienced a real hurricane, and they may be taking it lightly," Holloway tells National Geographic News. "And even some of the people who were here during Camille are not worried. But just because your house stood up during Camille don't mean it'll stand up to this hurricane."
Late Sunday night: Thousands of New Orleans residents who are unable to leave town or have chosen not to leave seek shelter in the Louisiana Superdome.
MONDAY, AUGUST 29
2 a.m.: Hurricane Katrina turns north toward the Louisiana coast, but the storm's strongest winds have diminished slightly to about 155 miles an hour (250 kilometers an hour). The center of the storm is about 130 miles (210 kilometers) from New Orleans. A weather buoy about 50 miles (80 kilometers) east of the river's mouth reports waves at least 40 feet (12 meters) high.
5 a.m.: The hurricane's strongest winds are now about 150 miles an hour (240 kilometers an hour), and its eye is about 90 miles (145 kilometers) from New Orleans and about 120 miles (195 kilometers) from Biloxi.
7 a.m.: Hurricane Katrina's eye is about to come ashore in Plaquemines Parish, Louisiana. The hurricane's strongest winds are about 145 miles an hour (235 kilometers an hour). The eye is about 70 miles (115 kilometers) from New Orleans.
8 a.m.: Mayor Ray Nagin reports that water is flowing over one of New Orleans's levees.
9 a.m.: The eye is about 40 miles (65 kilometers) from New Orleans and is expected to pass just to the east of the city. The storm's strongest winds are about 135 miles an hour (215 kilometers an hour).
11 a.m.: The hurricane's eye comes ashore again near the Louisiana-Mississippi border. The storm's strongest winds are about 125 miles an hour (200 kilometers an hour). Katrina's front-right quadrantwhich contains its strongest winds and peak storm surgeslams into Biloxi and Gulfport, Mississippi, with devastating force, destroying much of both cities.
Meanwhile, a major levee in New Orleans has failed (See "New Orleans Levees Not Built for Worst Case Events"). Water is pouring through the 17th Street Canal, and the city is beginning to flood.
1 p.m.: Hurricane Katrina continues to weaken as it moves farther inland. Its strongest winds are about 105 miles an hour (170 kilometers an hour).
3 p.m.: The center of the hurricane is about 20 miles (30 kilometers) west of Hattiesburg, Mississippi. Its winds are down to about 95 miles an hour (155 kilometers an hour).
TUESDAY, AUGUST 30
11 a.m.: The National Hurricane Center issues its last advisory on the storm that once was Hurricane Katrina. The storm has maximum winds of about 35 miles an hour (55 kilometers an hour), and its center is dumping heavy rainfall on Tennessee.
During the day: Floodwaters continue to pour into New Orleans from breaks in the city's levees (See "Photo Gallery: New Orleans People, Pets Flee Flood").
WEDNESDAY, AUGUST 31
During the day: Health and Human Services Secretary Michael O. Leavitt declares a public health emergency in Louisiana, Mississippi, Alabama, and Florida (See "New Orleans Floodwater Fouled With Bacteria, Chemicals"). Meanwhile, Louisiana Governor Kathleen Blanco orders that all remaining residents leave New Orleans (See "Photo Gallery: New Orleans Refugees Struggle, Looters Plunder"). But buses and trucks aren't available to carry out the order.
THURSDAY, SEPTEMBER 1
2 p.m.: On national television New Orleans Mayor Ray Nagin issues a "desperate SOS" for help from the federal government (See "Photo Gallery: Agony Reigns in Katrina's Aftermath"). Nagin says there's no food for those who took shelter at the Louisiana Superdome and New Orleans convention center.
FRIDAY, SEPTEMBER 2
During the day: A convoy of U.S. National Guard troops and supply trucks arrives in New Orleans and distributes food and water to residents stranded at the Superdome and convention center. Congress approves 10.5 billion dollars (U.S.) in aid for Hurricane Katrina rescue and relief, and President George W. Bush signs the bill.
The work of repairing the city's levees, pumping out the floodwaters, and finding homes for tens of thousands of displaced residents is underway.
Willie Drye is author of Storm of the Century: The Labor Day hurricane of 1935, published by National Geographic.
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