(Adds second death in Kansas, details on storm forecasts for Missouri and Illinois)
By Kevin Murphy
KANSAS CITY, Mo., Feb 26 (Reuters) - A powerful winter storm that has left at least three people dead in its wake barreled toward Chicago on Tuesday, threatening to snarl the evening commute with heavy snow, ice and winds while leaving nearly all of the U.S. Plains buried.
Blizzard conditions in Oklahoma, Texas and parts of Kansas, which were still digging out from a winter storm last week, shut highways and forced flight cancellations.
The storm dumped up to 17 inches (43 cm) of snow on Amarillo, Texas, and whipped Kansas City, Missouri, with winds of up to 30 miles (48 km) per hour, and on Tuesday was rolling to the east and north toward Chicago and then Detroit.
More than 440 flights were canceled on Tuesday morning, according to Flightaware.com, including 240 arrivals and departures at Chicago O'Hare International Airport and 104 at Kansas City International Airport, nearly all of its flights.
The Chicago area was expected to be hit by 3 to 6 inches of heavy snow after a mix of rain, sleet and snow changes over to all wet snow on Tuesday afternoon, the National Weather Service said.
Before that, the storm was expected to drop up to 8 inches of snow on five cities straddling the Mississippi River on the border of Illinois and Missouri with wind gusts up to 35 mph (56 kmh) causing blowing and drifting, the National Weather Service said.
Highways in the Texas and Oklahoma panhandles and parts of Kansas were closed because of heavy and drifting snow that cut visibility and forced flight cancellations at airports across the region.
The storm has contributed to at least three deaths, two in Kansas and one in Oklahoma.
A woman died and three passengers were injured Monday night on Interstate 70 when their pickup truck rolled off the icy roadway in Ellis County, Kansas Governor Sam Brownback said. Earlier Monday, a man was killed when his car veered off the interstate in Sherman County near the Colorado border, he said.
"We urge everyone to avoid travel and be extremely cautious if you must be on the roads," said Ernest Garcia, superintendent of the Kansas Highway Patrol.
In northern Oklahoma, one person died when the roof of a home partially collapsed in the city of Woodward, said Matt Lehenbauer, the city's emergency management director.
"We have roofs collapsing all over town," said Woodward Mayor Roscoe Hill Jr. "We really have a mess on our hands."
Heavy, wet snow weighted down tree branches and power lines in Kansas City on Tuesday, snapping some lines and causing about 40,000 customers to lose power, Kansas City Power & Light said. Schools and government offices were closed.
Governors in Texas and Oklahoma had declared states of emergency in the areas struck by the snowstorm to speed assistance to people who need it. Interstates and other highways were closed across the Texas and Oklahoma panhandles.
Areas around Amarillo and Lubbock received more than a foot (30 cm) of snow during the storm, which had cut visibility to near zero on some roads at the time, Texas transportation officials said.
In addition to the winter storm, National Weather Service forecasters on Tuesday issued tornado watches across central Florida and up the eastern coast to South Carolina. (Reporting by Kevin Murphy in Missouri and David Bailey in Minneapolis; Editing by Lisa Von Ahn, Barbara Goldberg and Nick Zieminski)