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As for the president, on Thursday Sept 1, four days after Katrina hit, he said, "I don't think anybody anticipated a breach of the levees."

On a conference call, which President Bush participated in as Katrina approached, the director of the National Hurricane Center, Max Mayfield, said: "I don’t think any model can tell you with any confidence right now whether the levees will be topped or not, but that's obviously a very, very grave concern."

Today, Mayfield told NBC News that he warned only that the levees might be topped, not breached, and that on the many conference calls he monitored, "Nobody talked about the possibility of a levee breach or failure until after it happened."

The response will be dissected for years. But on Thursday, disaster experts and frustrated officials said a crucial shortcoming may have been the failure to predict that the levees keeping Lake Pontchartrain out of the city would be breached, not just overflow.

...Local, state and federal officials, for example, have cooperated on disaster planning. In 2000, they studied the impact of a fictional "Hurricane Zebra"; last year they drilled with "Hurricane Pam."

Neither exercise expected the levees to fail. In an interview Thursday on "Good Morning America," President Bush said, "I don't think anyone anticipated the breach of the levees." He added, "Now we're having to deal with it, and will."

...Army Corps personnel, in charge of maintaining the levees in New Orleans, started to secure the locks, floodgates and other equipment, said Greg Breerwood, deputy district engineer for project management at the Army Corps of Engineers.

"We knew if it was going to be a Category 5, some levees and some flood walls would be overtopped," he said. "We never did think they would actually be breached."