(Mankato, MN) — The blowing and drifting snow is making travel dangerous in the open areas especially in southern Minnesota. MnDOT says many state highways and Interstate 90 remained closed overnight in southwest and south-central Minnesota. No travel advisories were posted in a number of counties including Brown, Cottonwood, Jackson, Martin and Watonwan. Officials say the road closures and no travel advisories will be lifted once visibility and conditions improve. More than 500 flights have been cancelled at Minneapolis-St. Paul International Airport since Wednesday.