More than 10 inches of snow fell in parts of New England as snow, sleet and freezing rain swept across the Northeast before tapering off Sunday.

Atmospheric river conditions could bring multiple feet of snow to the northern Sierra Nevada. Other areas face a risk of flooding as the ground becomes increasingly saturated.

“So many of you have never seen an event like this,” Louisiana’s state climatologist warned, with New Orleans facing possibly the most snow it has ever seen.

Closures of schools, airports and businesses were taking effect in areas from southern Texas to Florida and South Carolina. Snow and ice could bring major travel disruptions and power outages.

Heavy snow is expected on Sunday in the Northeast before the coldest air in several years descends across much of the country starting on Monday, forecasters warned.

The snow is likely to fall on Sunday from the Appalachians to New England. New York City may see its largest snowfall in years.

A winter storm was sweeping across a wide swath of the South on Friday. Atlanta’s airport issued a ground stop after a plane was evacuated onto a snowy runway.

Hazardous snow, sleet and freezing rain disrupted travel plans and caused power outages in the Mid-Atlantic region, as bitter cold set in.

The storm caused thousands of flights and dozens of train trips to be delayed or canceled. At Ronald Reagan National Airport in Washington, all runways were closed Monday evening.

All highways in northeastern Kansas were closed on Sunday evening, bringing traffic to a standstill in some parts.

Officials are bracing for a dreadful mix of sleet, snow and freezing rain that is forecast to hit from Kansas to Virginia this weekend.

The Arctic air arrives this weekend and could linger into mid-January.