A massive winter storm blanketed much of the central United States Thursday, dumping heavy snow, sleet and freezing rain, and even prompting tornado warnings with its high winds.

Tens of millions of people in 24 states were expected to be affected by the storm before it peters out when it reaches the Great Lakes on Friday or Saturday.

But that won't bring clear skies. The storm was pulling a second system up from the Gulf of Mexico that is expected to smother parts of the East Coast with up to two feet (60 centimeters) of snow on Saturday and Sunday.

The National Weather Service said as much as 17 inches (43 centimeters) of snow had fallen in parts of Colorado and Kansas by Thursday afternoon.

Other areas from Oklahoma to Ohio were expected to get between six and 18 inches by the time the storm blows over.

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

Roads and even major highways became completely impassable in some areas and treacherous ice rinks in others, prompting officials to urge people to stay home or pack emergency supplies if they need to drive somewhere.

At least two deaths were reported as a result of the hazardous driving conditions.

Alexander Cody, 18, was killed when his pickup slid into oncoming traffic on an Oklahoma highway Wednesday, KOCO news reported. Kristina Leigh Ann Allen, 19, died after another woman lost control on a snowy Nebraska highway and struck her car Wednesday, WOWT news reported.

Scattered power outages were also reported as ice weighed down power lines and strong winds knocked down trees.

The blinding snow was even illuminated by lightning in some areas -- a phenomenon known as "Thundersnow."

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 conditions were 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."

Meanwhile a third storm system was dumping snow in the mountains of Oregon and Washington state, welcome news for local ski resorts.

The precipitation brought by the winter storm could also be welcome in other areas of the country.

"The good news is that at least two of these systems are helping to relieve long-term drought," National Weather Service meteorologist David Roth told AFP.