© Joe Raedle, Getty Images
Ernie Darby hugs his son Davis as they search for belongings in their Joplin, Mo., home after Sunday's tornado.
An unrelenting storm season spread havoc in Oklahoma, Kansas and Texas while devastated Joplin, Mo., hunkered down for a night punctuated by tornado sirens.

Five people died and three children were critically injured when tornadoes touched down west of Oklahoma City at rush hour, officials said. Two more died in Kansas when high winds tossed a tree into a vehicle. And at least one twister disrupted air travel in North Texas. Travelers were hustled to storm shelters and, at Dallas-Fort Worth International Airport, flights were canceled while crews inspected aircraft for hail damage and runways for debris.

In Joplin, meanwhile, the death toll from one of the nation's deadliest tornadoes rose to 122, with more than 750 injured. And exhausted residents couldn't catch a break. Tornado sirens sounded about 9:30 p.m., and again shortly after 10. Although twisters didn't touch down, a tornado watch remained in effect until 3 a.m. Officials warned that high winds could blow the massive debris around, inflicting more damage.

Photos: Devastation in Joplin, Mo.

Earlier in the day, as Joplin's sky filled with dark clouds, residents raced to salvage what they could and rescue teams dug through splintered ruins in a desperate hunt for survivors.

Searchers, some aided by dogs, checked ruined buildings, including a half-collapsed Wal-Mart, a Home Depot and a large apartment complex. Two survivors were found Tuesday, in addition to seven the day before.

On Kentucky Avenue, Tim Jasinski, a 44-year-old contractor, loaded bundles of sheetrock into the back of his pickup, then added a bicycle belonging to one of his seven children. He cast a glance back at his house, a century-old bungalow he had been renovating before the tornado touched down Sunday.

"It's gone," he said. "It's just a matter of how long before it topples. We're just salvaging what we can."

The tornado, which packed winds of more than 200 mph, was the eighth deadliest in U.S. history, according to the National Oceanic and Atmospheric Administration. It was the worst since 1947, when 181 people died in Woodward, Okla. Officials in Joplin said 8,000 structures had been damaged, many beyond repair.

It was one of a series of devastating tornadoes that have struck the Midwest and South this spring, causing more than 480 deaths.

The scene Tuesday on Kentucky Avenue was typical of what was happening all along the six-mile-long swath of destruction in this city of 50,000 in southwestern Missouri, close by Oklahoma and Kansas. Homeowners, joined by friends and family, gathered up personal items and frantically tried to shore up tottering houses as the sky turned from a welcome hazy blue to an ever-darker and more threatening gray.

Before Sunday, this was a pleasant, leafy block of early 20th century bungalows with converted attics. Many of those attics were lopped off by Sunday's storm. Oaks lay across lawns, roofs and living rooms, shorn of their bark and leaves. Yards were heaped with torn-out insulation, mud and battered belongings.

Across the street from Jasinski, John Mott stood on his debris-covered lawn, sipping a Coke and considering the state of his home.

"The inside is kindling," he said. "The south wall is separated from the foundation and I'm trying to prop it up so it can survive another night."

Mott was wistful, remembering how friendly the street had been, how folks had looked out for one another. His eyes focused on a devastated bungalow across the street where an elderly man used to live. The man died before the storm.

"He lived there since 1958, and I'm glad he didn't get to see what happened to his house," Mott said.

His attention returned to how he would survive the night ahead. "Pray," he said. "We don't have a lot of choice."

While some people insisted on staying in their battered houses, others had no choice but to seek shelter. At Missouri Southern State University in Joplin, 143 people took refuge in a basketball arena; elsewhere, 34 people stayed in a church. Public health officials administered tetanus shots and about 190 National Guard troops helped search for survivors.

Police made several looting arrests, and the city instituted a 9 p.m. to 6 a.m. curfew in the damaged zone, Chief Lane Roberts said at a news conference.

Addition Authors: Matt Pearce and Mitchell Landsberg