A major winter storm is spreading across the US Midwest, affecting holiday travel and cutting power to hundreds of homes. The worst of the storm is expected to hit late today and dump up to 2 feet of snow by Christmas Day. Six motorists in Nebraska, Kansas and New Mexico, were killed due to icy road while more than 260 flights from Chicago's airport were cancelled. The latest storm began in the south-west on Tuesday, causing blizzard-like conditions and travel chaos, before spreading to the east and north. A spokesman for the National Weather Service said the storm was moving across the centre of the country, basically from the Canadian border to Texas and spreading from west Colorado to Illinois. The governor of South Dakota issued a state of emergency, and urged residents to stay off the roads until the storm passed.<br/>