Schools in Texas have cancelled classes and shoppers have stocked up on milk, pet food and other supplies to prepare for the wintry blast which has brought freezing temperatures, ice and snow to much of the nation.
Earlier this week, many in Texas were basking in spring-like temperatures.
However, the National Weather Service has issued winter storm and ice warnings for parts of Texas, Oklahoma, Arkansas, Mississippi, Missouri, Illinois and Indiana ahead of what some are calling “Ice Friday”.
The storm system has already dumped up to two feet of snow in parts of Minnesota and Wisconsin.
In the Dallas area, agencies and residents are still haunted by the fiasco of a frozen Super Bowl week two years ago, when an inadequate response to a winter storm crippled the region and left visitors stranded on impassable highways.
This time, all of north Texas mobilised before an expected half-inch of freezing rain began to come down.
Many schools, colleges and universities in Dallas, Fort Worth and outlying districts cancelled classes. Organisers of the Dallas Marathon, however, had not yet decided whether to cancel Sunday’s race.
In Missouri, the city of St Louis opened its first cold-weather shelter of the season and warned residents to dress in layers.
Officials in Rapid City, South Dakota decided it was too cold for ice skating and closed the local rink.