[UPDATE 1:30 a.m.] The Oklahoma Medical Examiner's Office has been told to expect about 40 additional bodies, CNN reports, citing spokeswoman Amy Elliott. The official death toll will not rise until the bodies are processed, but this report suggests it will reach 90.

[UPDATE 12:15 a.m.] Two hospitals tell the Associated Press they've been treating more than 120 patients hurt in the tornado, including about 50 children.

Spokeswoman Brooke Cayot said nine of 57 patients being treated at the Integris Southwest Medical Center were listed in critical condition. Nineteen were in serious condition and 29 were listed in fair or good condition. She said five of the patients were children who have been treated and released.

OU Medical Center spokesman Scott Coppenbarger said his hospital and a nearby children's hospital are treating approximately 65 patients, including 45 children. He said the patients' injuries ranged from minor to critical.

[UPDATE midnight EDT] President Barack Obama has declared a state of disaster and ordered federal aid.

From the White House statement: "The President today declared a major disaster exists in the State of Oklahoma and ordered federal aid to supplement state and local recovery efforts in the area affected by severe storms and tornadoes beginning on May 18, 2013, and continuing.

"The president's action makes federal funding available to affected individuals in the counties of Cleveland, Lincoln, McClain, Oklahoma and Pottawatomie.

"Assistance can include grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses, and other programs to help individuals and business owners recover from the effects of the disaster.

"Federal Emergency Management Agency said that residents and business owners who sustained losses in the designated counties may apply for assistance by registering online at http://www.DisasterAssistance.gov or by calling 1-800-621-FEMA(3362) or 1-800-462-7585 (TTY) for the hearing and speech impaired. The toll-free telephone numbers will operate from 7 a.m. to 10 p.m. (local time) seven days a week until further notice."

[UPDATE 10:50 p.m. EDT'] On the Enhanced Fujita damage scale of tornadoes, the Oklahoma twister was probably a 4 or 5, the highest level, with winds reaching 200 miles per hour, Russell Schneider, director of the National Oceanic and Atmospheric Administration’s Storm Prediction Center in Norman, Okla., told the Washington Post.

“It’s a very wide swath of very intense damage, a large number of structures almost totally destroyed,” Schneider said. “That in and of itself is usually indicative of a violent tornado, EF4 or EF5.”

[UPDATE 10:15 p.m. EDT] Rescue workers continued searching the rubble of Plaza Tower Elementary School in Moore Monday night for some two-dozen missing children following a huge tornado that leveled part of the town, Oklahoma Lt. Gov. Todd Lamb said.

In an interview on CNN, Lamb said rescue workers rushed in fading light to try to find the children at the school, which took a direct hit from a tornado packing winds of up to 200 miles per hour. At least 51 people have been confirmed dead in the tornado, which struck at midafternoon Monday.

[UPDATE 9:25 p.m. EDT] Live stream updates from KFOR in Oklahoma City can be seen here.  

Monday's devastating twister is estimated to be two to three times the magnitude of the record-breaking 1999 Oklahoma tornado that whipped through the same area.

ABC News adds that besides the 51 dead, 105 casualties were being treated at hospitals, and 65 of them were said to be children.

The number of fatalities is expected to rise, KFOR reported, and it is not known how many of the dead are children. Several children were pulled alive from the rubble, after the twister tore the roof off, crumbled walls and ripped the playground apart.

James Rushing, who lives across from the Moore elementary school, told the Associated Press he watched the tornado tear into the school. "About two minutes after I got there, the school started coming apart," he said.

[UPDATE 8:58 PM ET] The death toll has risen to 51, according to the latest update from the Oklahoma medical examiner's office given to NPR, and is expected to continue to rise.

[UPDATE 8:24 PM ET] The Oklahoma state medical examiner's office says at least 37 are dead, with the toll expected to rise, the AP reports. It is unknown how many of the victims are children. 

[UPDATE 8:02 PM ET] KFOR-TV is now reporting that children have died at Plaza Tower Elementary School. Rescuers have so far pulled seven dead bodies from the wreckage, and said they do not expect to find any more survivors. There could be up 30 children still inside the building. 

[UPDATE 7:40 PM ET] All children at both Briarwood Elementary School and Plaza Towers Elementary School in Moore, Okla., have been accounted for, ABC News is reporting. Rescue workers are still visiting individual residences in the area searching for victims. (8:03 PM ET: This report appears to be incorrect in light of new information.)

[UPDATE 6:05 PM ET]: The National Weather Service has a graphic with a preliminary comparison looking at the path of today's tornado and the path of a May 1999 tornado that killed dozens:


[UPDATE 6:00 PM ET]: Raw video of the tornado's aftermath from the Associated Press:

[UPDATE 5:57 PM ET]: Around 75 children were taking shelter in Plaza Towers Elementary, one of the schools that was hit, according to local news station KFOR.

One man interviewed by KFOR rode out the storm inside a horse stall:


[UPDATE 5:44 PM ET]: Memphis news station WMCTV has a terrifying time-lapse video of the tornado's movements, as seen from a helicopter.

[UPDATE 5:40 PM ET]: Storm chaser Ben Holcomb tweeted a picture of the massive tornado as it crossed Sooner Road at SE 134th Street in Oklahoma City:[[nid:1271195]]

and as the twister was crossing I-35:


[UPDATE 5:31 PM ET]: Some local forecasters and storm chasers are saying the Moore tornado looks like it rates an EF5 --the highest rating a tornado can receive on the Enhanced Fujita scale. EF5 tornadoes have wind speeds of more than 200 miles per hour.

After a weekend of severe tornadoes, Oklahoma is getting pummeled again Monday, with areas just outside of Oklahoma City taking major damage. Early pictures and video flowing in from the scene paint a grim portrait.

A large tornado – reportedly two miles wide, according to CNN affiliate KFOR --  moved through Moore, Okla., a suburb of Oklahoma City, causing major damage.

Briarwood Elementary School was hit by the twister, CBS reporter Tim Williams tweeted. Emergency officials are saying there are at least 100 injuries so far, though it’s unknown how many of those are from the school.

Moore's Plaza Towers Elementary School likewise suffered severe damage. A photo from local news station WHNT showed the devastation:[[nid:1271179]]

"It's just destroying everything,” storm chaser Spencer Basoco said, according to CNN. “There's so many homes in the air right now. The motion on this storm is sickening.”

Live video from CBS News below: