Blizzard conditions in parts of southern Minnesota made travel there dangerous Wednesday morning, the weather service office in the Twin Cities warned on social media. Heavy snow and strong northerly winds slowed travel across much of the Twin Cities, southern Minnesota and western Wisconsin, the weather service said.

The winter storm could impact up to 170 million people across more than 20 states from the southern Plains to the Midwest and East, AccuWeather said.

Storms that swept through Texas and Oklahoma brought high winds and rain, overturning tractor-trailers and damaging roofs. Power outages were climbing in the storm’s wake, with nearly 400,000 customers without power in Texas, about 30,000 in Louisiana and another 25,000 in Mississippi, according to PowerOutage.us.