GALVESTON, Texas (CNN) --
iReporter Carlos Ortega says there's "not an inch that isn't damaged" in his Galveston, Texas, neighborhood.
1 of 4 more photos » "Galveston cannot safely at this point accommodate its population," City Manager Steve LeBlanc said at a news conference.
And LeBlanc warned those who heeded evacuation warnings not to return to the island.
"We would go in a downward spiral if everybody started coming back," he said. "Our resources are stretched to the max."
President Bush will be in Texas Tuesday to survey Ike's damage. At least 14 Texas refineries closed in the hours before the hurricane hit, taking away more than 20 percent of the nation's oil capacity, the Associated Press reported. Across the nation, gas prices soared for the third straight day, many jumping a whole dollar.
Galveston residents had been warned as Ike approached the Texas coast to leave or face "certain death" from its 12- to 15-foot storm surge. iReport.com: Facing the deadly storm
On Monday, LeBlanc called the island "unhealthy and unsafe" and said the cleanup could take months.
"Sometimes the aftermath of the storm is worse than the storm itself," Galveston Mayor Lyda Ann Thomas said. "There's nothing to come here for right now. ... Please leave."
It could be four weeks before power is restored in the city, officials said.
North of Galveston, Texas Gov. Rick Perry urged residents who evacuated Houston, the nation's fourth-largest city, not to hurry back to their homes either. Watch the governor discuss Texas' troubles »
About 150,000 of the 220,000 residents who evacuated ahead of the storm were still out of their homes Monday, said Judge Ed Emmett, chief executive of Harris County, which includes Houston.
Power has been restored to at least 500,000 customers in the Houston area, according to the Harris County Office of Homeland Security and Emergency Management, but another 1.5 million people in the state still have no electricity. Thousands have no clean drinking water, though Houston officials said they may lift a boil-water order by Monday afternoon. See the aftermath of Ike »
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Emmett estimated that damage costs in Harris County alone would run into the billions of dollars, but it could have been worse.
"Galveston Island is called a barrier island for a reason. It served as a barrier for Houston," he said. iReport.com: Shattered Houston buildings
Ike and its remnants left at least 27 people dead from the U.S. Gulf Coast to the Great Lakes. The remnants moved into Canada early Monday.
But hurricane-force winds from the storm were felt as far north as Kentucky, and heavy rains flooded streets in Chicago, Illinois. See Chicago's swamped streets
Deaths related to the storm were reported in Louisiana, Arkansas, Indiana, Missouri and Ohio as well as Texas.
The toll could go higher. Chambers County, Texas, Judge Jimmy Sylvia said late Sunday that there is nothing left of Oak Island, a city on the coast in Galveston Bay. Smith Point, to the south, has "mounds and mounds of debris," the judge said, and he fears they may find bodies in the rubble. Watch how Ike wiped out neighborhoods »
On Sunday, a Galveston County sheriff's official said three bodies were pulled from storm wreckage in Port Bolivar, bringing to 10 the number of reported deaths in Texas linked to Ike.
Trees toppled by Ike killed eight people -- four in Indiana, three in Ohio and one in Arkansas.
Louisiana Chief Medical Officer Louis Cataldie confirmed four deaths as a result of the Ike -- two in Terrebonne Parish and two in Jefferson Davis Parish. Watch how Ike flooded one Louisiana parish »
Two people drowned in Indiana and another in Missouri.
Two others died in the St. Louis, Missouri, area, but the cause of their deaths was unclear, said Missouri State Emergency Operations Center spokeswoman Susie Stonner.
Houston's post-Ike supplies coming, officials say
Ike damage prompts weeklong curfew in Houston
iReport.com: Were you in Ike's path? Send your pics, video
In Depth: Hurricane Ike
Wind gusts as high as 74 mph ripped the roof off a Delta Airlines hangar at Cincinnati/Northern Kentucky International Airport, according to an Associated Press report. The airport's control tower had to be evacuated during the worst of the storm, the AP said.
More than 340,000 Louisville Gas and Electric Co. customers were without power Monday morning, CNN affiliate WLKY-TV reported.
Across the region, more than 1.3 million people were without power, the AP reported.
"Over 90 percent of our customers are without service," Kathy Meinke of Duke Energy, which serves southwest Ohio and northern Kentucky, told the AP.
About 2.1 million homes and businesses in Texas and Louisiana were without power Monday. iReport.com: Ike soaks, smashes Texas home
Flooding was also a problem in the Midwest.
Chicago authorities asked Illinois Gov. Rod Blagojevich to issue a disaster declaration after rainfall Saturday in the Windy City broke a single-day record that had stood for more than two decades.
Saturday's pounding rain was not related to Hurricane Ike. Remnants of Tropical Storm Lowell, which moved in from the Pacific, got caught up with a cold front, sending moisture into the region.
But on Sunday, as the remnants of Ike -- by then a tropical depression -- worked their way into the country's heartland, heavy rain drenched much of the region, including Illinois.
More than 5,000 people were evacuated because of flooding in Munster, Indiana, according an AP report.
"The water was nothing but a trickle in the middle of the street, and by the time we decided what to do it was too late," George Polvich, a Munster resident rescued by boat, told the AP. "There was, like, 3 feet of water."
Kishwaukee River waters were rising overnight in Sycamore, Illinois, forcing dozens of mobile home residents from their homes, CNN affiliate WIFR-TV in Rockford, Illinois, reported.
But one resident said his troubles were minor compared to those on the Texas coast.
"Nobody came in with a helicopter to evac anybody so how bad do we have it? My carpet got wrecked, I'm gonna have to put some new floors in. Stuff can always be replaced. Pets, people, not so much," Vince Prew told WIFR.