A massive storm spreading across the US West into the Northern Plains and Midwest this week forced hundreds of schools to close, grounding air travel and making roads difficult — if not impossible — to navigate. More than 50 million Americans were under winter weather advisories on Wednesday morning as the storm moved across a wide section of the western and northern US and into the East. The storm wreaked havoc on morning air travel, with about 3,500 flights delayed or cancelled across the nation, including 470 flights into and out of Minneapolis, Minnesota, <a href="http://flightaware.com/"><i>Flightaware</i></a> reported. Up to 60cm of snow and winds of up to 97kph were expected in some spots during the day and into Thursday, the National Weather Service said. The agency issued winter storm, blizzard and high-wind advisories for a broad part of the western and north-central US. Snow falling at a rate of 5cm an hour and gusty winds will make travel conditions treacherous and perhaps impossible in parts of the Northern Plains and the Upper Midwest, the forecaster said. Among the hardest-hit cities in the Midwest was Minneapolis, where about 50cm of snow and 72kph winds were expected to create whiteouts. “We are bracing for what is likely to be one of the largest snowstorms in Minnesota history,” St Paul Mayor Melvin Carter said at a news conference. That would be the most for a February snowstorm and one of the top five heaviest falls of all time in a city already renowned for its brutal winters, the state's Department of Natural Resources said. Local officials declared emergencies in Minneapolis and neighbouring St. Paul, and motorists were told not to be out on the roads. Minneapolis's school system said it would hold classes remotely for more than 29,000 pupils for the rest of the week. Dozens of school districts cancelled classes in the Dakotas, Colorado and Wyoming. While much of the US will deal with cold, snowy weather over the week, parts of the South may have record high temperatures. Some spots in the South may have temperatures that are dozens of degrees warmer than some places in the Northern Plains, the forecast showed. Orlando could hit a record high of 32ºC, while the temperature is expected to drop to minus 27ºC in Billings, Montana, the service said. Starting on Wednesday, the storm will move into the Upper Midwest with “some of the greatest impacts in Minnesota and Wisconsin”, said Frank Pereira, a forecaster with the NWS Prediction Centre in College Park, Maryland. The storm also pounded California and brought a mix of snow and sleet to the East, including New England, where forecasters warned motorists to beware of slick roads. A rare blizzard warning was issued for Los Angeles County mountains, the first issued by the weather service since 1989. The growing frequency and intensity of such storms, interspersed with extreme heat and dry spells, are symptoms of climate change, experts say. <i>Reuters contributed to this report</i>
