(CNN) Workers at Denver International Airport handed out blankets and toiletries to about 800 passengers who were stuck there overnight because of a snowstorm.

The airport canceled 546 flights Tuesday and 725 flights were delayed, airport spokeswoman Emily Williams told CNN.

The National Weather Service said Wednesday morning that the airport got 7.7 inches of snow in 24 hours. Some areas around Denver received up to 12 inches.

Denver International Airport got more than 7 inches of snow.

Denver Public Schools were also closed Wednesday because of the storm.

The snow was tapering off Wednesday and flights were getting back to normal, airport spokeswoman Alex Renteria told CNN.

The airport did have to cancel 21 flights Wednesday and 171 were delayed by 15 minutes or more.

Airport officials urged travelers to arrive two hours early if they had a flight Wednesday.

The airport hopes the stranded passengers will be able to get flights Wednesday or Thursday, Renteria said.

Winter weather warnings and advisories stretch from Colorado south into Texas, and north into the Midwest, including Kansas City, Missouri, and Chicago, as a winter storm and much colder air move east.

Southwest Airlines warned that the weather could disrupt flights to and from several Midwestern cities, including Denver; Amarillo, Texas; Wichita, Kansas; Kansas City; Lubbock, Texas; and Chicago Midway International Airport.