A massive winter storm blanketed much of the central United States Thursday and looked set to keep dumping heavy snow, sleet and freezing rain for days as it makes its way slowly towards the east coast.

The National Weather service reported that as much as 15 inches (38 centimeters) of snow had fallen in parts of Colorado and New Mexico by Thursday morning and warned that many areas would get at least a foot (30 centimeters) by the time the slow-moving storm passed.

Those living on the southern end of the storm were faced with a dangerous mix of freezing rain and sleet and Arkansas was on an ice storm warning.

"Heavy snow along with some blowing and drifting snow will result in very poor visibility at times and cause snow packed and treacherous driving conditions," the weather service warned.

"The most significant ice accumulations are expected on trees, power lines and untreated highways."

The governor of Missouri declared a state of emergency as the storm lashed the midwestern state with a dangerous mix of ice and as much as 10 inches (25 centimeters) of snow overnight.

"Missouri stands ready to help communities in need and to deploy the resources to keep folks safe," Governor Jay Nixon said. "I urge all Missourians to keep a close eye on the weather and avoid unnecessary travel."

The state of Kansas shuttered government offices Thursday to keep non-essential workers off the treacherous roads and scores of business owners and school officials followed suit.

The blizzard was so intense in some areas that snow plows were getting stuck and ambulances had trouble getting patients to hospitals.

"The roads throughout Wichita (Kansas) are snow-packed and many are impassible," the Sedgwick county emergency management office warned on its website. "Please stay home and off the roads unless absolutely necessary."