Volunteers and professional disaster workers from the Washington region began the launch yesterday of what will be a far-reaching relief effort to help Gulf Coast victims of Hurricane Katrina.

They tried to contact their hurricane-buffeted colleagues in Louisiana and Mississippi, readied canine search teams and headed south in mobile canteens.

In Fairfax County, a 34-person rescue team that includes structural engineers and hazardous materials experts prepared for deployment after being alerted by federal officials. A similar team from Montgomery County, complete with watercraft and high-tech search cameras and audio equipment, also was getting ready to leave.

It was a day heavy with news monitoring and arrangement making, marked by the anxieties and uncertainties inherent in such a massive effort to equip relief workers and direct them to the hardest hit areas.

"I know I'm a small part of a large operation," said Julie Wright, executive director of the Alexandria chapter of the American Red Cross, speaking by cell phone yesterday from an emergency food delivery truck on her way to a staging area in Little Rock. She expected she might be rerouted once higher-level Red Cross executives decided where she and her team of volunteers would be most useful. "It's a huge logistical effort," she said.

It also can be a dangerous one.

William R. McLaughlin, a Federal Emergency Management Agency employee from Manchester, N.H., was killed Sunday afternoon on Interstate 81 south of Roanoke when a tire blew out on a truck he was driving toward the area Katrina was slated to hit. His truck ran off the road and rolled over, according to Virginia State Police Sgt. Robert Carpentieri.

McLaughlin was in a truck convoy with fellow members of the Mobile Emergency Response Support detachment out of Maynard, Mass. The group sets up satellite communications and other high-tech support for relief efforts, according to Cindy Taylor, a spokeswoman.

State and federal officials said they did not know the cause of the tire blowout.

Michael D. Brown, undersecretary of homeland security for emergency preparedness and response and head of FEMA, issued a statement thanking McLaughlin for "his selfless work serving disaster victims across the nation."

Local religious groups were seeking donations and setting up channels to deliver aid.

Jerry Collins, director of disaster response at Alexandria-based Catholic Charities USA, spent yesterday making hourly attempts to reach some of his group's administrative workers, who were inside New Orleans's Superdome with about 10,000 others who did not leave the city.

"We're waiting to hear from our people on the ground. Our efforts go to long-term recovery," Collins said.

Executives at Adventist Community Services, a religious charity in Silver Spring, helped organize a network of warehouses yesterday to supply Gulf Coast residents whose homes were damaged or destroyed by violent wind and rain.

"We have 51 local disaster-response units, and that helps tremendously," said Executive Director Sung Kwon. "It's a very stressful time, individually and in the community by and large, and at a time like this we really come together . . . and individuals look out beyond themselves. Even though this is very tragic, we do experience a positive outcome out of disaster," he added.

Red Cross volunteer Dan Rogers, a retired executive from AT&T, left Manassas on Sunday, driving toward the Little Rock staging area. He and other volunteers are hauling hot and cold chests for food and beverages. Rogers, who became interested in volunteer work after teaching CPR decades ago in Pittsburgh, said he's ready to help faraway neighbors facing devastation.

They will hand out mops, brooms and meals.

"We'll go down the road and look for people who are trying to clean up their mess and ring a bell and serve them food," Rogers said.

Staff writers Jacqueline L. Salmon and Elizabeth Williamson contributed to this report.

Rod and Evi Hartung inspect the damage to their home in Pascagoula, Miss., after Hurricane Katrina made landfall. Washington rescuers set out for Mississippi and Louisiana yesterday.