A massive winter storm blamed for at least six deaths made travel nearly impossible in parts of the central United States Tuesday, the National Weather Service said.

"Blizzard conditions that caused fatal accidents and rendered highways impassable in five states crawled deeper into the Great Plains early Tuesday," the weather service said.

"Hotels filled up quickly along major roadways from eastern New Mexico to Kansas, and nearly 100 rescue calls came in from motorists in the Texas Panhandle."

Snow drifts reached 10 feet (three meters) in parts of Colorado after strong winds whipped at the 15 inches (38 centimeters) of snow had fallen since the storm began late Sunday.

Parts of New Mexico were blanketed by two feet of snow (61 centimeters) while Kansas got up to a foot of snow (30 centimeters) by Tuesday morning.

While the heaviest snowfall had mostly ended by midday Tuesday, blizzard conditions continued in many areas as strong winds of up to 50 miles (80 kilometers) per hour whipped up heavy white flakes, the weather service said.