ARAB, Ala. (AP) _ A pre-dawn tornado ripped across north Alabama today, killing three people and injuring more than 100, authorities said.

The dead, all in Arab, included a young child, Marshall County Coroner Dempsey Hibbs said.

At least one resident reported hearing no warning siren before the storm hit shortly after 5 a.m.

Less than an hour before that, lightning struck the office of the National Weather Service in nearby Huntsville, forcing its evacuation.

But a warning was issued shortly before the storm hit by the service's office in Birmingham.

Karen Berry of Arab said ``this roar woke me up,'' trees were flying through the air and the power went out.

``Normally they give us a siren warning, but they didn't this morning,'' she said. ``There was nothing.''

Officials at Guntersville-Arab Medical Center said 66 people were treated, with 13 admitted and four transferred to Huntsville for additional care. They said they knew of 40 other people taken to two other hospitals.

Farm buildings collapsed, metal buildings peeled open, trailers and homes were torn apart, and toys and furniture were strewn amid the rubble in the tornado's wake. Pink insulation was left hanging from trees.

Authorities said the tornado apparently hit a subdivision in the rural community of Joppa, where about a dozen injuries were reported, and then hit Arab, some three miles to the east.

A roof blew off a section of an apartment complex in Arab, but authorities who searched the rubble found no injured people there. Robert Reynolds of the Arab Fire Department said there were other happy surprises amid the destruction.

``We found a 1-year-old baby under two trailers,'' he said. ``He was sitting there, not making a sound.''

The storm lifted a wooden A-frame home from its cement foundation and carried it about 40 feet before dropping it _ with the residents still in their bed. Both Ricky and Dianne Fortenberry escaped serious harm.

``They had to dig us out,'' she said, standing atop the splintered wreckage and pointing to the mattress where they had been sleeping. As she spoke, a little neighbor girl sat in a nearby car and cried.

The coroner said the dead were a 4-year-old girl and two men, all killed in separate locations. An earlier report of four dead was erroneous, he said.

Gary Petti, meteorologist in charge of the Birmingham office, said his office had taken over weather monitoring responsibility for Marshall County after the 4:20 a.m. lightning strike at the Huntsville office.

Petti said the Birmingham radar detected ``a clear signature for a tornado'' and issued a warning at 5 a.m., only minutes before the tornado hit.

The loss of the Huntsville office delayed the warning only seconds, Petti said, but it kept the weather service from issuing the warning that alerts people who have special weather radios in their homes.

It was not immediately clear if the problem had affected the town's siren.

Petti said the weather service had issued a tornado watch _ meaning conditions were present that could result in tornados _ at about 4:15 a.m., but with most people sleeping at the time, it probably did little good.

In addition to the three tornado deaths, a fourth person died in a traffic accident that may have been caused by rain-slicked roads, authorities said.

Arab (pronounced AY rab) is 30 miles south of Huntsville and has a population of about 6,300.

Lee Helms, acting director of the Alabama Emergency Management Agency, said there were reports of homes damaged and trees and power lines down in several other counties.

The storm system also brought heavy rain and tornado warnings to parts of Mississippi and Georgia. Flooding caused problems, particularly in Mississippi, where several towns reported rainfall totals of more than 5 inches.

In Greenville, Miss., floodwater pushed into a number of homes and businesses, forcing emergency crews to work throughout the night sandbagging threatened areas. The small town of Sunflower also battled to stay ahead of rising waters.

In Georgia, a few residents of a mobile home park near Kennesaw, northwest of Atlanta, were evacuated this morning when a creek flooded. The area got nearly 2 1/2 inches of rain in 24 hours.