DENVER - A spring storm brought a strange brew of tornadoes, heavy snow, rain and hail to Colorado on Tuesday, damaging buildings and forcing schools and highways to close and stranding buses carrying dozens of schoolchildren.

The same system also brought flooding, tornadoes and high winds to many parts of the Plains. Storms overturned several mobile homes in Texas.

Four buses in Colorado carrying at least 60 children were stranded after being unable to travel in the storm, which dropped more than a foot of snow in about two hours, said Rob Finley, assistant fire marshal for El Paso County. Children in those buses were rescued and taken to shelters.

Officials were trying to reach another stranded bus late Tuesday, but it was unclear whether any children were still aboard or had been evacuated.

"It was zero visibility. ... One bus was stranded between two power lines," Finley said.

Gov. Bill Ritter activated the Colorado National Guard to help rescue the buses Tuesday evening. They were stuck in snow and 60 mph winds about 30 miles east of Colorado Springs, Ritter's spokesman Evan Dreyer said.

As many as 70 passenger vehicles also were caught in the storm, Dreyer said.

In Eagle Pass, a city of 26,000 about 145 miles east of San Antonio, authorities were surveying damage and assessing injuries Tuesday night after high winds, hail heavy rain and reports of tornadoes, said Arturo Garcia, the city's fire marshal. Several mobile homes were overturned.

Streets flooded throughout North Texas, and roofs peeled off homes as storms began moving through Tuesday afternoon. Tornado sirens rang in several counties, and drivers and residents had to be rescued from flooded cars. Thousands lost power.

A tornado damaged several buildings near the small town of Wild Horse about 110 miles southeast of Denver, but no injuries were reported, the Cheyenne County Sheriff's Department said.

"I was terrified," said Wild Horse resident William Skinner, 47, of Wild Horse. "It was right there, by my neighbor's, just about 200 feet away."

A second twister was reported near the Colorado-Kansas line about 35 miles east of Wild Horse.

Evergreen, Colo., in the foothills west of Denver, reported 16 inches of snow, and other foothills towns had up to 14 inches. Some schools were closed.

Tumbling boulders, a fallen power line, accidents, slick pavement and poor visibility forced nearly a dozen road closures, including on Interstates 25 and 70.

A jackknifed semi backed up traffic for nearly 20 miles on southbound I-25 between Denver and Colorado Springs.

Hail the diameter of quarters peppered parts of southeastern Colorado, and authorities said some rural roads were blocked by flooding from heavy rain in northeast Colorado, northwest Kansas and southwest Nebraska.

Several inches of rain fell in parts of Nebraska, weather officials said.