(CNN) -- Grocery store shelves are bare. Food left in refrigerators has rotted in the absence of electricity. Houston and Galveston are hungry.



Ashia Turner and her family, from Galveston, wait at a shelter for a bus that will take them to a hotel on Tuesday.



The Houston Food Bank is "utterly overwhelmed with people asking for help," its president, Brian Greene, said Tuesday. The food bank needs 500,000 pounds of food a day for the next six weeks to satisfy the "staggering" needs of Texans who have no food or water after the storm, he said.



"People don't grasp just how many people live here," said Greene, who was executive director of New Orleans' Food Bank when Hurricane Katrina struck the Gulf Coast in 2005. He lost his home in Katrina, and lived at the New Orleans food bank for weeks using a garden hose as a shower.



Most of the Houston food bank's volunteers' homes were damaged and they don't have power.



"It's a very similar situation that I saw following Katrina: when the caregivers themselves [are] victims, it just becomes difficult on a far larger scale than you would think," he said. iReport.com: How are you getting by after Ike?



He pointed out that while Katrina's devastation was spread over a greater area, more people have been affected by Hurricane Ike.



Greene said the food bank normally distributes aid through local charities, churches and other faith-based organizations. But many were wiped out by the storm or are unable to function because of the lack of electricity or phone service.



The Federal Emergency Management Agency has said several times that they are constantly shipping two days' worth of food every day to make sure supplies do not wane. FEMA has established at least 60 distribution sites across the region to give away water, ice and food. There are long waiting lines at those stations crowded with thousands of people. iReport.com: Long lines for help



Gov. Rick Perry on Tuesday issued an emergency order that authorized public utilities to lay temporary power lines to restore electricity to 1.5 million customers.



Houston Mayor Bill White spoke at a 9 p.m. news conference about food distribution. "If we could figure out how to get a big block of ice on your doorstep, we'd do it," he said. The city is working to get people refrigerated food, but he cautioned, "There's a limited number of [FEMA] trucks" that contain supplies.



Fuel is being shipped back to the region, he said. Motorists should stop topping off their tank and only pump the amount of gas they need.



Thousands of people remain in shelters throughout the state. FEMA said it was instituting a transitional sheltering program, allowing some evacuees who are unable to return home to stay in hotels or motels. FEMA will pay for the lodging directly to hotels and motels, the agency said. iReport.com: Ike evacuees get help in Austin



Galveston was so ravaged that city officials told the 15,000 to 20,000 people who stayed on the island during Ike to leave. For those who evacuated, the message was: Stay away. There's not enough clean drinking water and if people came back it would result in a "downward spiral" that officials cannot handle right now, Galveston City Manager Steve LeBlanc said Monday.



"Sometimes the aftermath of the storm is worse than the storm itself," Galveston Mayor Lyda Ann Thomas said Monday. "There's nothing to come here for right now. ... Please leave."  Watch how Ike wiped out neighborhoods »



In Houston, a curfew remained in place, banning citizens from the streets from 9 p.m. to 6 a.m. iReport.com: Shattered Houston buildings



A bottled or boiled water advisory for the Houston area was not lifted as had been hoped -- with the exception of Bellaire, which gave the OK for its tap water Tuesday. Houston city officials said water in one location was being retested.



Harris County, which includes Houston, said it had crews working to clear roads in downtown Houston, and said most streets were
How many Texans are without power? How many people are still in shelters? Who needs 500,000 pounds of food a day for the next 6 weeks? How many are without power? What is the name of the hurricane? What hurricane caused damage in Galveston? How much food is needed per day by the food bank?
1.5 million Thousands of Houston 1.5 million customers. Katrina Ike. 500,000 pounds of food a day
question: How many Texans are without power?, answer: 1.5 million | question: How many people are still in shelters?, answer: Thousands of | question: Who needs 500,000 pounds of food a day for the next 6 weeks?, answer: Houston | question: How many are without power?, answer: 1.5 million customers. | question: What is the name of the hurricane?, answer: Katrina | question: What hurricane caused damage in Galveston?, answer: Ike. | question: How much food is needed per day by the food bank?, answer: 500,000 pounds of food a day