Updated

Ranchers, pilots and snowmobilers on Wednesday searched for thousands of cattle trapped by heavy snow and high drifts in Colorado, Kansas and New Mexico.

Eight Colorado National Guard helicopters and a C-130 cargo plane were dispatched in the state's campaign to save livestock herds snowed in by back-to-back holiday blizzards. Volunteer snowmobile search-and-rescue groups from elsewhere in the state joined the effort on the ground.

Photo Essay: Blizzard Buries the Plains

"We think there are probably 30,000 head out there that are at risk that we're having to make sure we feed," said Maj. Gen. Mason Whitney of the Colorado Guard.

An undetermined number of cows died in southwestern Kansas. One feedlot owner in Haskell County, Kan., said he lost 450 cattle and 20 dairy cows.

"I don't know what we are going to do, how we are going to dispose of them," County Commissioner Gene Ochs said of the carcasses.

Emergency crews worked through the long weekend to rescue stranded motorists, evacuate people with health problems and deliver food, water and medicine to the region's snowbound residents.

Utilities in sections of Nebraska, Kansas, Oklahoma and Colorado worked around the clock to restore electricity to tens of thousands of homes and businesses, but officials said it could take weeks for some of the most isolated, rural customers.

At least 21,000 customers in western Kansas were without power, as were an estimated 15,000 customers in Nebraska, about 2,500 in Oklahoma and about 2,300 in Colorado. Nebraska state officials estimated tens of millions of dollars in damage to power lines and other equipment.

Mary Hock said her family has been without electricity at their farm northwest of Holdrege, Neb., since early Saturday. They camped out with a neighbor who has a generator for a couple days.

"Even those of us here in rural Nebraska who are relatively sturdy are extremely dependent on electricity," she said.

The storm was also blamed for at least 13 deaths.

The storm covered more than half the nation's major cattle-feeding areas, said Kevin Good, a senior analyst with Cattle Fax, a cattle market information service.

Don Ament, Colorado agriculture commissioner, said a Lamar-area rancher said he could find only half of his 600-head herd.

"You've got cattle walking over the tops of fences and just roaming around," Ament said.

Leonard Pruett, the region's agriculture extension agent for Colorado State University, said there was about a 5 percent mortality rate in affected herds, but he had no specific numbers. The Colorado Cattlemen's Association estimated there were 100,000 to 200,000 cattle in the region's open range.

On Wednesday, ranchers rode with pilots to spot cattle and creeks for water in Colorado. Crews in smaller helicopters landed near frozen streams and used sledgehammers to chop ice from the water.

Soldiers delivered about 500 bales of hay Tuesday to cattle unable to get through the snow to grass and water, Whitney said.

In New Mexico and Kansas, crews also dropped hay to livestock that have gone without feed for days.

Heavy snow near rancher Karen Doherty's northeastern New Mexico home, including a 30-foot-deep snowdrift, kept her and her husband from reaching most of their 500 head of cattle.

"We're getting kind of concerned," she said. "The cattle here in the area near the house, we can take care of them. In the outlying pastures, there's no way."

New Mexico's Gov. Bill Richardson and Nebraska Gov. Dave Heineman asked federal authorities for a disaster declaration, which would provide low-cost loans to eligible applicants and help state and local governments pay for items like snow removal or fence repairs.

"We are taking every step possible to provide relief and assistance for those farmers and ranchers facing the prospect of catastrophic losses," Richardson said.

Meanwhile, a separate storm in Alaska blanketed parts of Anchorage with 16 inches of snow on Wednesday, prompting the University of Alaska Anchorage to close early.

The snow wreaked havoc on traffic, with 53 collisions reported and more than 100 vehicles in distress or in ditches, Anchorage Police Department Lt. Paul Honeman said.