Dr. Walter Maestri is the director of emergency management for Jefferson Parish, La., which borders New Orleans.
He told co-anchor Hannah Storm, "The greatest risk is really from tidal surge flooding, given the fact we're surrounded on … basically 3½ sides by water.
"New Orleans exists below sea level, basically in a bowl," he said. "It resembles a soup bowl, surrounded on all sides by levees, the entire metro area. If the levees are topped by the tidal surge flooding, the water comes into the bowl and remains, because every drop of water that falls here has to be pumped out."
Maestri says that "absolutely" brings with it the potential for that water to be somewhat toxic because of the large number of chemical and oil businesses in the area.
"We have major storage facilities directly adjacent to most of our waterways," he said.
He added that the mechanisms put in place before Katrina stormed ashore are substantial.
"(Washington) has made the full resources of FEMA and other agencies available to us," Maestri said. "We pre-positioned a lot of those agencies and their resources so we know we have their full support right now.
"We have everybody in our area, parish personnel and so forth, basically hunkered down, waiting for the storm to pass over.
"The biggest problems right now is the lack of power. We're basically in the black, 90 percent in the metro area."