Exactly how many is anybody's guess, because authorities had no sure way to track those who defied evacuation orders. And the number of people reported missing after the storm, whose death toll stands at 17 in Texas, is fluctuating.
Search-and-rescue crews cleared out Wednesday after plucking survivors from Galveston and the devastated Bolivar Peninsula, and authorities are relying on Red Cross workers and beach patrols to run welfare checks on people named by anxious relatives.
"We don't know what's out there in the wilds," said Galveston County medical examiner Stephen Pustilniks. "Searchers weren't looking for bodies; they were looking for survivors."
As the hurricane closed in, authorities estimated that 90,000 people ignored evacuation orders along the Gulf Coast. Post-storm rescuers in Galveston and the peninsula removed about 3,500 people, but another 6,000 refused to leave.
Nobody is suggesting that tens of thousands died, but determining what happened to those unaccounted for is a painstaking task that could leave survivors wondering for months or years to come.
Authorities concede that at least some of those who haven't turned up could have been washed out to sea, as at least one woman on the peninsula apparently was, and that other bodies might still be found.
"I'm not Pollyana. I think we will find some," said Galveston County Judge Jim Yarbrough, the county's highest-ranking elected official.
Pustilniks' office brought in two refrigerated tractor-trailers to store bodies until autopsies are performed. One sat in front of the medical examiner's office Wednesday morning with a sign on the side: "Jesus Christ is Lord not a cuss word."
By the afternoon, five deaths had been reported in Galveston County: one man who drowned in his pickup, another found inside a motel, two dialysis patients who could not get to their treatment, and a woman with cancer whose oxygen machine shut down.
The stench of rotting animals and livestock polluted the once-picturesque community of Crystal Beach, where about two dozen people stayed behind. One survivor told of seeing a friend wrenched from the rafters by the storm's fury and swept out to sea.
In evacuation shelters hundreds of miles from the coast, displaced residents -- like the loved ones of victims of 2005's Hurricane Katrina -- scrolled through address books and blog postings and anxiously dialed relatives, friends and neighbors not heard from.
On an Internet forum where survivors listed notes giving their whereabouts and asking for news of the missing, the messages revealed the growing anxiety and frustration of those desperate for some word about their loved ones.
"Anyone know Rosa who lived on the end towards the bay in gilchrist on Dolphin rd? She didnt have a vehicle and last we heard she was staying?"
And this message: "If ANYONE KNOWS WHERE MY FATHER IS OR KNOWS IF HE IS ALIVE AND WELL, PLEASE PLEASE LET ME KNOW. I AM HEARTBROKEN!!"
In Galveston County, where about 15,000 residents stayed behind, officials did not have an exact number of missing residents. The Red Cross is helping track down the missing by setting up registries at shelters and sending workers on welfare checks, Yarbrough said.
At Galveston's emergency management center, 12 phone lines rang constantly with calls from people trying to find relatives. As the calls came in, the city's beach patrol would go to the homes and check.
Sometimes, the searches end in relief. The Red Cross quickly found an elderly Galveston couple reported missing Wednesday morning by relatives in Wyoming, Yarbrough said.
The search echoes the chaos following Katrina in 2005, when bodies were turning up more than a year after the storm as ruined homes were dismantled and families returned after months away. Katrina killed more than 1,600 people.
In that storm, there was no way to track people who left the city. The situation worsened when more than 100,000 New Orleanians who took refuge in Houston had to scatter again a few weeks later for Hurricane Rita.
Authorities opened a center in Baton Rouge, La., to take reports of people who were missing. And just as Ike survivors are doing now, volunteers there turned into amateur detectives -- digging through Web sites that sprouted for missing families and calling nursing homes and hospitals.
The center for the missing closed nearly a year after Katrina, when authorities said they had finally exhausted leads.
Brownsville resident Amy Woodside has posted several messages online trying to track down friends who may have succumbed to Ike.
"I'm worried about everybody who is still unaccounted for," she said. "We may never find some of them."