NEW ORLEANS -- Even though Hurricane Gustav did not wreak the destruction expected when it struck the Gulf Coast on Monday, officials yesterday said they were not ready to allow many of the 1.9 million Louisiana residents who had evacuated to return to their homes.

While the worst was avoided -- there were no major levee breaks of the sort that inundated New Orleans after Hurricane Katrina in 2005 -- Louisiana Republican Gov. Bobby Jindal cautioned that the state still faces major hurdles before life returns to normal.

"This was a serious storm that has caused major damage," Mr. Jindal said, as the hurricane's trailing edge continued to dump rain across the state. "This is a challenge that is not going away overnight. We did not have the levee breeches, but we have major challenges from Hurricane Gustav."

Massive power outages were among the most immediate problems, with some towns completely without electricity. More than 130 transmission lines and dozens of substations were knocked out of service, meaning Gustav was surpassed only by Hurricanes Katrina and Rita in 2005 in the destruction caused to the region's electric grid.

About 1.4 million customers are without power in Louisiana, and vast portions of the New Orleans and Baton Rouge metropolitan areas have been knocked off the national electricity grid, said Kevin Kolevar, assistant secretary of energy for electricity delivery and energy reliability.

Of immediate concern were about a dozen hospitals that had limited electricity service, raising the possibility that some of their 800 patients will need to be evacuated -- in addition to hundreds already removed to more secure facilities, Mr. Jindal said. State and federal officials said they were moving fuel to hospitals and other key facilities to ensure that they can continue to run generators.

To clear debris, distribute supplies and secure communities isolated by the storm, thousands of National Guard troops, federal law enforcement officers and other emergency workers were being deployed.

Meanwhile, Gustav continued to spawn bad weather. The National Weather Service reported that a tornado touched down last night in New Orleans's West Bank neighborhood, and there were reports of flooding along several rivers in residential neighborhoods on Lake Pontchartrain's northern shore, roughly 20 miles north of New Orleans.

In Washington, the White House announced that President Bush will visit Louisiana today to view the havoc caused by Gustav. He plans to make several stops in the state, but the schedule was yet to be finalized last night.

According to a preliminary Army Corps of Engineers estimate, Gustav caused about a tenth as much damage as hurricanes Katrina and Rita,. Maj. Gen. Don Riley, the Corps' deputy commanding general, said Gustav damaged roofs of about 25,000 homes, compared with 200,000 damaged by the 2005 Gulf Coast hurricanes. The Corps estimated that it will need to remove 10 million cubic yards of debris, compared with 120 million cubic yards after the 2005 storms.

Mr. Jindal said the state is deferring to local authorities to decide when different areas are safe enough for residents to return. Hundreds of buses were waiting to bring people home, and the state is also working with Amtrak and airlines to coordinate their returns once local leaders approve.

Parishes that sustained little damage announced that residents could begin returning today. Those with more significant destruction said residents will need to wait as late as Friday.

To get residents back to New Orleans, Mayor C. Ray Nagin announced a phased plan, in which employees of major corporations and retailers are expected to return to the city today, with the rest of city residents allowed back starting possibly tomorrow. Yesterday, authorities established checkpoints on major roads leading into the city to turn away those who tried to come back prematurely.

In New Orleans, things began to return to some semblance of normalcy yesterday. The National Football League announced that the Saints, who had been practicing in Indianapolis, will return to the Superdome for their Sunday season opener against the Tampa Bay Buccaneers.

Many of the estimated 10,000 residents who rode out the storm emerged from their homes, relieved at the city's narrow escape. Under partly sunny skies, they walked dogs, cruised the empty streets on bikes and sought out restaurants, which were slowly reopening.