The idea of the Big One, a hurricane doomsday scenario of floods and death, has long haunted this city, and Hurricane Katrina looked to many like its terrifying incarnation.

But on Monday evening, as crowds began filtering back onto city streets and inspecting the damage from glass-shattering winds and surging water, many here said with conviction that they were relieved.

"This wasn't it," concluded Demetrius Ralph, 42, as he surveyed the scene in the shuttered French Quarter while out walking his dog. Streets were littered with debris, but they were not covered with water, as many had feared.

In outlying eastern areas, where officials had yet to completely assess the damage, entire neighborhoods were flooded up to the rooflines. Scores of people fled to their attics, punched holes in their roofs, and awaited rescue by boat or helicopter.

Downtown, Canal Street and other fabled New Orleans promenades were rendered almost impassable by fallen trees, awnings, street signs and stoplights, and the destruction to hotel high-rises dealt a severe blow to the city's tradition of "vertical evacuation."

Instead of finding solace above the floodwaters, the vertical evacuees encountered a wind so severe that it imploded the windows, lashed the rooms with drenching rain and sent them scurrying for cover. Hundreds of guests at the downtown Hyatt Regency hotel pitched camp Sunday night on blankets in a ballroom with little more than inches separating one family from another.

"Did you see the side of the hotel where my room was?" asked Ed Freytag, 46, of New Orleans, with a room on the hotel's southern exposure, which bore the brunt of Katrina. "It was like a bomb went off."

Still, there was a palpable sense of relief among some longtime city residents that New Orleans, which sits six to eight feet lower than the surrounding waters, had avoided a far worse catastrophe.

For the Massa family, huddled in their front room around the light of a single gas lamp, the prospect of leaving New Orleans for the first time in at least a decade seemed far more frightening than Hurricane Katrina.

Despite the insistent evacuation orders relayed first by television and then on their battery-powered radio after the electricity blackout at 5:15 a.m., Janice Massa, 60, and her parents Vincent, 82, and Ruth, 81, decided to stay and face the storm in their two-story house on the outskirts of New Orleans.

Fearful of venturing outside too often to inspect the damage, they spent the day sitting in the gloom, with the wind whistling through the door like a frenzied kazoo player. The heat of the gas lamp, coupled with the lack of air conditioning, made the room almost unbearably stuffy.

"The way I feel is that if God had decided that our time was up -- then we would go regardless of where we were," said Janice, who indicated that her mother is unable to walk more than a few feet and her father has diabetes and a defibrillator. "At least this way, if it happens, we would be at home, not on a highway, not knowing where we were going. They say go towards Texas, but my fear was to be caught out on the road with my parents."

The trio even turned down an offer from a close family friend in the police department, who suggested they accompany him to a secure family shelter at police headquarters. They decided Janice's 13-year-old grandson, who is in her care, should go there alone. The adults argued that others would have greater need of the shelter's special attention.

"You do what you have to do, and you put the rest in God's hand," said Janice.

So they taped up the mailbox, stuffed newspaper down the side of the door, rolled down the hurricane shutters and put their faith in both God -- like many in New Orleans, they are Catholic -- and their house, built with plaster and stucco by Janice's grandfather in the 1950s.

By yesterday afternoon it appeared their prayers had been answered: As the winds started to quell, the only damage appeared to be the loss of two ridge tiles from their roof. "We were very lucky," Janice said.

Others in their neighborhood were less fortunate: One block away, a 20-foot oak tree crashed through the roof of a two-story house, and overhead cables crisscrossed the road in pools of rain. Electricity and water are not expected to return for days.

Officials estimated that tens of thousands of people defied repeated requests to evacuate the New Orleans area, despite forecasts of winds of up to 150 mph and warnings of floods of up to 20 feet.

Those who fled on Saturday and Sunday told of lines of up to nine hours to reach the safety of Texas and beyond. But many of those left behind were seniors, fearful of such a long journey and scared of what they would find at the other end.

"All my children went out of town, and they all wanted me to accompany them. But it took my eldest and his five children nine hours to get from Hattiesburg to Jackson, Mississippi," said Catherine Morrow, 78, who lives next to the Massas.

As the storm passed just to the east of the city, those roads that remained accessible saw only a handful of cars -- many driving the wrong direction to avoid trees, pylons and other obstacles. Large pools of water would form rapidly, cutting off roads in minutes.

Some drivers, who defied official advice not to travel and became boxed in by floods, ended up having to sit out the storm in their cars. "I don't know how much longer I will be here," said Katerina Fukova, a cleaning woman from the Czech Republic who is living and working in New Orleans. She had been sitting for 30 minutes on a stretch of road overlooking Interstate 10, having been forced to abandon her journey because of flooding.

Chest-deep water dumped by Hurricane Katrina collects in New Orleans streets late in the afternoon.Power poles and trees are pushed over in a flooded street in Gretna, La., after Hurricane Katrina struck with winds topping 145 mph in some areas. An unidentified resident in the top-floor window of a house awaits rescue from high waters in the 8th Ward of New Orleans.