Images: Oklahoma residents start cleanup after devastating tornado

TULSA, Okla. - The first batch of severe weather in this year's tornado season devastated an Oklahoma mobile home park, as storms across the area damaged buildings, tore off roofs and left debris strewed across roads. One person was killed and several were injured.

Tens of thousands of Oklahoma residents were without power early Thursday as officials assessed the damage.

Tulsa County Sheriff's Capt. Billy McKelvey said one person was killed in the mobile home park in the Tulsa suburb of Sand Springs, which he said could accommodate 40 to 50 trailers.

"It could have been much worse," he said.

Joe Sellers, a National Weather Service meteorologist, said survey teams would assess the damage Thursday but that it was likely a tornado that hit Sand Springs.

Gov. Mary Fallin declared a state of emergency for 25 Oklahoma counties that were hit hardest by the storm, including the state's two largest - Oklahoma and Tulsa counties.

"We're still assessing the damage across Moore, Yukon, other areas of the state, especially in the Tulsa area," Fallin said Thursday after touring an elementary school in the Oklahoma City suburb of Moore, where a roof was torn off and many of the classrooms were soaked with water. "We've been down this road before. We know what to do."

Twenty-four people died in a top-of-the-scale EF5 tornado in Moore in 2013, and a small twister hit the town on Wednesday night. Others formed along a line from southwest of Oklahoma City to east of Tulsa, and some touched down in the Ozark Mountains of northwestern Arkansas.

Longtime Moore Mayor Glenn Lewis described Wednesday's storm as "kind of like a junior tornado for us."

Oklahoma Department of Emergency Services spokeswoman Keli Cain said at least nine people were hospitalized with injuries but that the total number of injuries wasn't yet known.

About 400 people were evacuated from the terminals at Will Rogers World Airport in Oklahoma City and took shelter in a pedestrian tunnel for about 45 minutes after the storm passed through the area Wednesday night, said airport spokeswoman Karen Carney.

The tornado season usually ramps up for parts of the U.S. in March, but until Tuesday - when a waterspout formed over an Arkansas lake - the U.S. hadn't had a tornado in more than a month.

Television video Wednesday evening showed roof damage in a Moore neighborhood - the Moore storm two years ago scraped lots to their foundations. A glass door at the Tulsa building that houses the National Weather Service office was smashed, and several cars in the parking lot lost their windows.

Power utilities reported just over 20,000 power outages Thursday morning, down from nearly 80,000 Wednesday night.

Weather patterns this month funneled cold air into much of the country, depriving the atmosphere of the warm, moist air necessary for forming bad storms for most of the month.

That all changed this week. Southerly winds pushed temperatures into the 70s and 80s across the Ozarks and Southern Plains, while weather fronts churned the air into Wednesday's storms.

Meteorologist Jeff Hood in Little Rock said a weak waterspout tornado briefly touched down in Bull Shoals Lake in Marion County in northwest Arkansas on Tuesday night. He said it will likely be classified an EF0 - the weakest tornado with wind speeds of 65 to 85 mph. A waterspout forms over water. The tornado never made it onto land, and there were no reports of damage.

Before this week, only about two dozen twisters had been recorded this year during a period when about 120 are typical. The last time the U.S. had no twisters in March was nearly 50 years ago, according to figures from the Storm Prediction Center in Norman, Oklahoma.