This Wikipedia article contains a detailed historical timeline of the events of Hurricane Katrina.
At approximately 8:14 AM CDT (1314 UTC) on Monday August 29, 2005, the New Orleans office of the National Weather Service issues a Flash Flood Warning for Orleans Parish and St Bernard Parish, citing a levee breach at the Industrial Canal.
The National Weather Service predicted three to eight feet of water and advised people in the warning area to "move to higher ground immediately." At 2:00 PM CDT (1900 UTC), New Orleans officials confirmed a breach of the 17th Street Canal levee.
There was also confirmation of breaches at two other canals.
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