Thousands of students in central and north areas in the U.S. state of Texas got a day off Thursday after an overnight storm brought about freezing rain, sleet and several inches of snow, causing cancellation of hundreds of flights and disruptions of traffic.

Schools throughout central Texas either delayed the start of classes or closed altogether because of the wintry weather. In northern Texas, the hardest hit area, where some places saw as much as seven inches (17.8 centimeters) of snow, schools also canceled classes for the whole day.

Flight tracking website Flightaware.com reported nearly 800 flights canceled Thursday at Dallas-Fort Worth International Airport, which had the highest snowfall since 1947.

Airport spokesman David Magana told the Dallas Morning News that the airport remained open though many travelers were still stranded. Crews were working around the clock to clear the taxiways.

Road traffic in some places were virtually brought to a standstill. Bus service in the city of Fort Worth was suspended because of the icy road.

The National Weather Service issued a winter storm warning for the Dallas-Fort Worth area through midday Thursday, when temperatures are expected to start rising above freezing.