Moore, Oklahoma (CNN) — Rescue workers raced against time and the oncoming night Monday looking for survivors after a powerful tornado blasted an area outside of Oklahoma City, leveling homes and killing at least 51 people.

At least seven of the dead were children from Plaza Towers Elementary School in Moore, which lay directly in the path of the monster storm’s wall of wind.
Seventy-five students and staff members had been huddled at the school when the storm hit, CNN affiliate KFOR reported.
As nightfall approached, determined searchers in hard hats dug in the debris for students possibly trapped, but authorities described the work as a recovery, not rescue, effort.
A father of a third-grader still missing sat quietly on a stool. Tears fell from his eyes as he waited for news of his son.
A temporary flight restriction was put in place over the school so that aircraft would stay away and emergency officials on the ground might hear any cries for help, said Lynn Lunsford with the Federal Aviation Administration.
After the ear-shattering howl of the killer storm subsided, survivors along the miles of destruction emerged from shelters to see an apocalyptic vision — the remnants of cars twisted and piled on each other to make what had been a parking lot look like a junk yard. Bright orange flames flew from a structure that was blazing even as rain continued to fall.
“Our worst fears are becoming realized this afternoon,” Bill Bunting, with the National Oceanic and Atmospheric Administration’s Storm Prediction Center, told CNN.
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“We certainly hope everyone heeded the warnings, but it’s a populated area and we just fear that not everyone may have gotten the word,” he said.
Bodies of those killed in the storm were being sent to Oklahoma’s office of the chief medical examiner, said the office’s Amy Elliott. Authorities had no immediate estimate on the number of injured.
The preliminary rating of damage created by the tornado is at least EF4 (winds 166 to 200 mph) — the second-most severe classification on a scale of zero to five — the National Weather Service said.
The tornado was estimated to be at least two miles wide at one point as it moved through Moore, KFOR reported.
Lando Hite, shirtless and spattered in mud, told the affilaite about the storm hitting the Orr Family Farm in Moore, which had about 80 horses.
“It was just like the movie ‘Twister,'” he said, standing amid the debris. “There were horses and stuff flying around everywhere.”
The tornado damaged several barns and he was worried many of the animals were killed.
Hite said he did not hear any warnings or sirens.
“It was real windy and everything stopped. Being from Oklahoma, I knew that was not right.”
Twenty patients, including 12 adults and eight children, were in trauma rooms at Oklahoma University (OU) Medical Center and at the Children’s Hospital at OU Medical Center, said spokesman Scott Coppenbarger.
Injuries ranged from minor to critical.
Moore Medical Center in Oklahoma was evacuated after it sustained damage, a hospital spokeswoman said.
All patients were being evacuated to Norman Regional Hospital and Healthplex Hospital, and residents injured in the storm were being told to go to those centers as well.
Norman Regional Hospital and the Healthplex were treating an unspecified number of people with “signs of trauma, lacerations and broken bones,” spokeswoman Melissa Herron said.