GALVESTON, Texas (CNN)  -- Rescuers in Galveston, Texas, were going door-to-door Saturday to check on the estimated 20,000 people who failed to flee Hurricane Ike, which has slowed to tropical storm status.



Park benches are strewn about in downtown Houston Saturday during Hurricane Ike.



As of Saturday afternoon, the Galveston Fire Department had taken 27 people to a shelter in a high school on the coastal island, which was without electricity or water pressure.



No casualties had been discovered so far in the search and rescue efforts, which have been hampered by heavy flooding and scattered debris.



Galveston had ordered evacuation of the island, but Galveston City Manager Steve LeBlanc said about 40 percent of the city's 57,523 residents chose to stay.



LeBlanc said the island would be closed while authorities assess damages, including to the causeway, which was in "bad shape" because of debris and road damage.



"The road buckled in a number of places," LeBlanc said. "Even if we opened it up you couldn't get through."



LeBlanc said 17 buildings on the island had been destroyed by fires, potent winds and a strong storm surge.



"We are in a recovery mode," Galveston Mayor Lyda Ann Thomas said in a press conference Saturday afternoon. "This eye came right over us, stayed a while and went on, but it brought a lot of damage to our city."



Ike was downgraded Saturday to a tropical storm 11 hours after it crashed ashore as a Texas-sized hurricane that walloped southeast Texas and southwest Louisiana.



In its wake, Ike -- which smashed into the coast as a Category 2 hurricane -- left four people dead, millions without power and destroyed homes and businesses along the Gulf Coast with powerful winds, rain and floodwaters.



President Bush declared 29 Texas counties and parts of Louisianans major disaster areas, making federal funds available for recovery from the storm.  View images of places hit by Ike »



Many people, like D.J. Knight of Pearlman, Texas, decided to ride out the storm at home, despite voluntary and mandatory orders issued across the region.



"The windows looked like they would explode," said Knight, a mother of two. "It just wouldn't stop."



Now, without electricity and surrounded by flooded roads and wreckage, Knight wonders whether it was worth enduring a sleepless night as the storm shook her home, located about halfway between Galveston and Houston.



"I didn't think it would be as bad as it was," she said. "It was horrible."



Knight is one of thousands waiting for assistance as the state rolls out the largest search and rescue operation in Texas history.  See pictures of the storm's destruction »



Gov. Rick Perry dispatched a 1,000-strong search and rescue team, including state troopers, pilots and members of the National Guard. Lines of National Guard trucks and ambulances were deployed from San Antonio even as officials are trying to grasp the extent of damage and the number of Texans stranded by the storm.



However, flooding and debris have impeded rescue efforts in some areas, adding to the uncertainty about how many Texans actually survived the storm.



"We're obviously concerned that there may be people we find who didn't get out and who are going to be in the rubble of what we uncover," said Secretary of Homeland Security Michael Chertoff. "We hope for the best, but I do want to prepare people for the fact they we may have some fatalities."



Chertoff said 40,000 Texans were in 250 shelters, and that food and water would be distributed in about 20 coastal locations as rescue efforts continue.



In Galveston, which bore the brunt of the storm, floods filled the historic district with 7 feet of water at the storm's peak, said Galveston County official Margaret Bunch.  Watch how a spunky little girl braved the storm »



A foot of water flooded the city's main courthouse, where many people rode out the storm, she said.



Wanda Collins' garage filled with 5 feet of water, ruining
What impeded rescue efforts? What was impeding rescue efforts? What's the name of the tropical storm? Who rode out the storm at home? How many were affected by the power outages? How many deaths were attributed to Ike? Where was the wereckage? What storm caused four deaths in Texas?
flooding and debris heavy flooding and scattered debris. Hurricane Ike, D.J. Knight of Pearlman, Texas, decided to ride 20,000 people four Galveston, Texas, Ike
question: What impeded rescue efforts?, answer: flooding and debris | question: What was impeding rescue efforts?, answer: heavy flooding and scattered debris. | question: What's the name of the tropical storm?, answer: Hurricane Ike, | question: Who rode out the storm at home?, answer: D.J. Knight of Pearlman, Texas, decided to ride | question: How many were affected by the power outages?, answer: 20,000 people | question: How many deaths were attributed to Ike?, answer: four | question: Where was the wereckage?, answer: Galveston, Texas, | question: What storm caused four deaths in Texas?, answer: Ike