DENVER - Pilots in a dozen plans were sent up over the plains of Colorado and Kansas on Monday to look for any snowbound travellers following a blizzard that dumped nearly 3 feet of snow and piled it in drifts 15 feet high.

Utility crews, meanwhile, struggled to restore electrical service to tens of thousands of homes and businesses.

The storm, which struck on Thursday, had dwindled to a line of heavy rainfall Monday along the East Coast, but a few roads in southeastern Colorado and western Kansas were still choked by snow.

"Life and safety are still the No. 1 priorities. We need to get the roads open so people can get out and deal with the situation," said Dick Vnuk, chief of operations for the Colorado Division of Emergency Management.

The huge storm was blamed for at least 12 deaths in four states. It was the second blizzard in as many weeks.

The Civil Air Patrol sent six planes into the air Monday over Colorado's Kit Carson County, where there had been reports of more people snowbound along Interstate 70, even though that highway was reopened Sunday for the first time in two days, patrol 1st Lt. Steve Hamilton.

On Sunday, CAP crews spotted two stranded vehicles with five people near the Kansas state line, along with several trucks whose crews chose to stay with their rigs, Hamilton said.

Some roads in southeast Colorado were choked by snowdrifts that measured 10 feet high and 15-foot drifts had been piled up in western Kansas.

Only a few sections of Kansas state highways were still closed Monday. "We're chipping away at it," said Ron Kaufman, spokesman for the Kansas Department of Transportation. Sunshine and slightly warmer temperatures were helping the effort Monday, he said.

The Kansas CAP and Highway Patrol sent up six planes aiding the search for possible snowbound travellers, and troopers driving I-70 were looking for stranded vehicles.

There was no way into or out of the western Kansas town of Sharon Springs on Monday but the community of 835 did not lose electricity, said Bill Hassett, manager of the town power plant.

"We're snowed under," Hassett said. "We're just in the process of digging out. We had total 36 inches of snow. Thank God we kept the lights on."

However, about 60,000 homes and businesses elsewhere in western Kansas still had no power, a state spokeswoman said, and utility officials said it could take more than a week to get them all back on line.

"We've gotten 3 inches of ice on wires and connectors, and that ice stays there until it gets above freezing," said Al Butkus, spokesman for the Kansas utility Aquila Inc.

Kansas National Guard troops had been out delivering generators, fuel and supplies to assisted living centers and shelters "to be sure people's lives were protected," said Sharon Watson, spokeswoman for Kansas Emergency Management.

Utility crews in the Oklahoma Panhandle had restored power to five whole towns blacked out by the storm, state Department of Emergency Management spokeswoman Michelann Ooten said Monday. Up to 6,000 customers still had no power Monday, mostly in rural areas, she said.

No widespread outages were reported in Colorado.

Ten traffic deaths were blamed on the storm in Colorado, Texas and Minnesota. A tornado spawned by the same weather system killed one person in Texas, and a Kansas man was reported dead in a rural home where a generator apparently was in use during the blackout.