"But you know, that's how it goes," Wilkerson said, his voice shaking. "You gotta be strong and keep going."
Wilkerson has been through tornadoes before, but nothing like this one.
"I still can't believe this is happening," he said. "You work 20 years, and then it's gone in 15 minutes."
All that remained in some places were "sticks and bricks," Fallin told reporters, calling the storm one of the "most horrific storms and disasters that this state has ever faced."
Police, firefighters, volunteers and nearly 180 National Guard troops joined forces Tuesday in searching the rubble and securing areas hit by the storm.
The weather wasn't cooperating with their efforts: National Weather Service crews surveying the damage in Moore reported rain, half-inch hail and 45-mph winds over the debris field.
The Oklahoma Highway Patrol asked motorists to steer clear of Interstate 35 near Moore to free up lanes for disaster response resources streaming into the area.
And so many people were showing up to volunteer that authorities had to plead with would-be rescuers to stay away.
Path of devastation
The tornado struck at 2:45 pm C.T. on Monday -- only 5 minutes after the first warnings went out, according to the National Weather Service.
Moore residents had about 30 minutes before the massive storm entered the western part of the city, CNN meteorologist Sean Morris said.
Among the many buildings struck by the storm were two schools: Plaza Towers and Briarwood elementaries.
Of the nine children killed by the storm, authorities said seven died at Plaza Towers Elementary School where the tornado ripped the roof off and collapsed walls.
Among the dead is 9-year-old Ja'Nae Hornsby, who was killed at Plaza Towers, her father told CNN's Anderson Cooper.
About 75 students and staff members were hunkered down in Plaza Towers when the tornado struck, CNN affiliate KFOR reported.
At one point, an estimated 24 children were missing from the school, but some later turned up at nearby churches.
On Monday, a father of a third-grader still missing sat quietly on a stool outside. Tears cascaded from his face as he waited for any news.
Even parents of survivors couldn't wrap their minds around the tragedy.
"I'm speechless. How did this happen? Why did this happen?" Norma Bautista asked. "How do we explain this to the kids? ... In an instant, everything's gone."