Why Bush and senior administration officials apparently believed that New Orleans had been spared the worst effects of the hurricane for hours after the city was already flooded:

THE NEW YORK TIMES Tuesday, August 30, 2005

Katrina Misses New Orleans, Heavily Damages Mississippi

By Joseph B. Treaster 
and Kate Zernike

Hurricane Katrina pounded the Gulf Coast with devastating force at daybreak Monday, sparing New Orleans the catastrophic hit that had been feared but inundating parts of the city and heaping damage on neighboring Mississippi where it tossed boats, ripped away scores of roof tops and left many of the major coastal roadways impassable.

Packing 145-mph winds as it made landfall, Katrina left more than a million people in three states without power and submerged highways even hundreds of miles from the center of the storm.

Officials reported at least 35 deaths, with 30 deaths alone in Harrison County, Miss., which includes Gulfport and Biloxi. Emergency workers feared they would find more dead among people believed to be stranded under water and collapsed buildings.

While Katrina proved to be less fearsome than had been predicted, it was still potent enough to rank as one of the most punishing hurricanes ever to hit the United States. Insurance experts said that damage could exceed $9 billion, which would make it one of the costliest storms on record.

In New Orleans, most of the levees held but the storm breached one and flood waters rose to rooftops in one neighborhood. Katrina's howling winds stripped 15-foot sections off the roof of the Superdome, where as many as 10,000 evacuees were sheltered.

Some of the worst damage reports came from east of the historic city of New Orleans with an estimated 40,000 homes reported flooded in St. Bernard Parish. In Gulfport, Mississippi, the storm left three of five hospitals without working emergency rooms, beachfront homes wrecked and major stretches of Mississippi's coastal highway flooded and unpassable.

"It came on Mississippi like a ton of bricks," the state's governor, Haley Barbour, told a midday news conference. "It's a terrible storm."

President Bush promised extensive assistance for hurricane victims and the Federal Emergency Management Agency was expected to be working in the area for months, assessing damage to properties and allocating ultimately what will likely be billions of dollars in aide to homeowners and businesses.

In Alabama, Louisiana, and Mississippi, the governors declared search and rescue their top priority, but said that high waters and strong winds were keeping them from that task, particularly in the hardest hit areas.

The governors sent out police and National Guard after reports of looting, and officials in some parts of Louisiana said they would impose a curfew.

Katrina was downgraded from Category 5 — the worst possible storm — to Category 4 as it hit land in eastern Louisiana just after 6 a.m., and in New Orleans, officials said the storm's slight shift to the east had spared them somewhat. The city is below sea level, and there had been predictions that the historic French Quarter would be under 18 or 20 feet of water.

Still, no one was finding much comfort here, with 100 mph winds and water surges of 15 feet. Officials said early in the day that more than 20 buildings had been toppled.