Even if it was not clear to anyone else in the government, the US Marines had figured they would be needed when Hurricane Katrina struck.
"Before the hurricane, I already told my guys to get ready, " said Lieutenant Colonel Kent Ralston, whose amtracks from the 4th Assault Amphibian Battalion, manned mostly by reservists, were soon grinding across highways from bases in Tampa and Jacksonville, Florida; Norfolk, Virginia and Gulfport, Mississippi.
Now amtracks -- amphibious assault vehicles, also called "hogs," which look like the spawn of a tugboat and a tank -- are sloshing through water 5.5m deep in a New Orleans residential area along Lake Ponchartrain east of the city center.
Aboard, in full battle gear, are infantry from Company B, 1st Battalion, 8th Marines, flown in from Camp Lejeune, North Carolina. Just last fall, they were in the forefront of bloody fighting in Fallujah.
Since last Thursday, when they began working, Marines have rescued about 500 stranded people, the main focus of their effort.
The Amtrack commanded by Master Sergeant Eric White patrolled for more than eight hours the other day, crisscrossing middle-class residential streets on the eastern edge of the city, occasionally lurching over submerged cars. But the only person the crew encountered was a white-bearded, obstinate Elmore Hays, in a pedal boat, who rebuffed calls to leave.
With about 1,700 Marines on the ground here and more on the way, Major General Douglas O'Dell, the task force commander, said the Marines would be concentrating much of their efforts in St. Bernard Parish, in Katrina's direct path and 90 percent inundated, and the neighboring Arabi district of New Orleans. They would be doing search and rescue, providing food and water, limited medevac and recovery of bodies.
"We had SA," said Lieutenant Colonel Dan Kelly, executive officer of the 24th Marine Expeditionary Unit, the nucleus of the task force, in the acronym-packed jargon that peppers speech here. It meant, in this case, situational awareness.
"Right after the hurricane, we briefed the staff," Kelly said. "Get the packs ready, get stuff together."
The huge, fast logistical effort -- 18,000 Meals, Ready to Eat and nearly 56,781 liters of water so far -- has poured some 2,000 Marines into the area. National Guardsmen and Army troops from the 82nd Airborne and 1st Cavalry, many of them veterans of Iraq, have also been deployed.
This reserve base, some 16km south of New Orleans, was ordered evacuated on Aug. 27, according to a sign taped to a door. It is now a bustle of activity with troops of all kinds passing through cots in the gymnasium. The airfield looks like the Woodstock of helicopters, with craft of all sizes buzzing about.
The key to the Marines' rapid deployment, according to O'Dell and other officers, is what he called their "expeditionary ethos," and their ability to mix and match various units, including reserves, to form a task force tailored to the problem at hand.
In this case, the amphibious vehicle detachments were key because of their ability to swim or crawl over obstacles. They were originally designed in the 1930s for hurricane rescue as the Roebling Alligator, Ralston said.
O'Dell, who is based in New Orleans in his normal post as commander of the 4th Marine Division, which in these times is heavily deployed in Iraq, said he had been told a week ago Sunday to begin planning, but had already begun on his own the night before.