LAFAYETTE, Tenn. — Daybreak revealed a battered landscape across the South today, as crews searching communities hit by a violent line of tornadoes fought through downed power lines, crumpled mobile homes, and snapped trees to find victims. At least 48 people were dead.

The storms swept across Kentucky, Tennessee, Mississippi, and Arkansas as Super Tuesday primaries were ending, ripping the roof from a shopping mall, blowing apart warehouses, and crumpling a campus’ dormitory buildings as students huddled inside.

Seavia Dixon, whose Atkins, Ark. was shattered, stood this morning in her yard, holding muddy baby pictures of her son, who is now a 20-year-old soldier in Iraq. Only a concrete slab was left from the home.

The family’s brand new white pickup truck was upside-down, about 150 yards from where it was parked before the storm. Another pickup truck the family owned sat crumpled about 50 feet from the slab.

“You know, it’s just material things,” Ms. Dixon said, her voice breaking. “We can replace them. We were just lucky to survive.”

As the extent of the damage quickly became clear, candidates including Senator Clinton, Senator Obama, and Michael Huckabee paused in their victory speeches to remember the victims.

Twenty-four people were killed in Tennesee, 13 killed in Arkansas, seven killed in Kentucky and four killed in Alabama, emergency officials said. Among the victims were Arkansas parents who died with their 11-year-old daughter in Atkins, about 60 miles northwest of Little Rock.

Ray Story tried to get his 70-year-old brother, Bill Clark, to a hospital after the storms leveled his mobile home in Macon County, about 60 miles northeast of Nashville. Clark died as Mr. Story and his wife tried to navigate debris-strewn roads in their pickup truck, they said.

“He never had a chance,” Mr. Story’s wife, Nova, said. “I looked him right in the eye and he died right there in front of me.”

Before dawn today, the system moved on to Alabama, bringing heavy rains and gusty winds, causing several injuries in counties northwest of Birmingham. There were at least two reports of tornadoes.

An apparent tornado damaged eight homes in Walker County, Ala., and a pregnant woman suffered a broken arm when a trailer home was tossed by the winds, a county emergency management director, Johnny Burnette, said.

“I was there before daylight and it looked like a war zone,” he said.

Northeast of Nashville, a spectacular fire erupted at a natural gas pumping station northeast of Nashville. The station took a direct hit from the storm, but no deaths were reported connected to the fire.

About 200 yards from the edge of the plant, Bonnie and Frank Brawner picked through the rubble of their home for photographs and other personal items. The storm completely sheared off the second story of the home.

“We had a beautiful neighborhood, now it’s hell,” Bonnie Brawner, 80, said.

Eight students were trapped in a battered dormitory at Union University in Jackson, Tenn., until they were finally freed. Tornadoes had hit the campus in the past, and students knew the drill when they heard sirens, the president of Union University, David Dockery, said. At least two dormitories were destroyed.

“When the sirens went off the entire process went into place quickly,” Mr. Dockery said. Students “were ushered into rooms, into the bathrooms, interior spaces.”

He said about 50 students were taken to the hospital and nine stayed through the night. But all would be fine, he said. The students “demonstrated who they are and I’m so proud of them.”

Well after nightfall yesterday, residents went through shattered homes in Atkins, a town of 3,000 near the Arkansas River. Around them, power lines snaked along streets and a deep-orange pickup truck rested on its side. A navy blue Mustang with a demolished front end was marked with spray paint to show it had been searched.

Outside one damaged home, horses whinnied in the darkness, looking up only when a flashlight reached their eyes. A ranch home stood unscathed across the street from a concrete slab that had supported the house where the family of three died.

In Memphis, high winds collapsed the roof of a Sears store at a mall. Debris that included bricks and air conditioning units was scattered on the parking lot, where about two dozen vehicles were damaged.

A few people north of the mall took shelter under a bridge and were washed away, but they were pulled out of the Wolf River with only scrapes, Steve Cole, of the Memphis Police Department, said.

In Mississippi, a department commander of the Desoto County Sheriff, Steve Atkinson, said a twister shredded warehouses in an industrial park in the city of Southaven, just south of Memphis.

“It ripped the warehouses apart. The best way to describe it is it looks like a bomb went off,” Commander Atkinson said.

Winter tornadoes are not uncommon. The peak tornado system is late winter through mid-summer, but the storms can happen at anytime of the year with the right conditions.

The tornadoes could be due to La Nina, the cooling of the tropical Pacific Ocean that can cause changes in weather patterns around the world. It is the opposite of the better-known El Nino, a periodic warming of the same region.

Recent studies have found an increase in tornadoes in parts of the South during the winter during a La Nina. On January 8, tornadoes were reported in Arkansas, Illinois, Missouri, Oklahoma, and Wisconsin. Two died in the Missouri storms.