A blast of arctic air is moving across the country, bringing subfreezing temperatures and a mix of freezing rain.
At least 15 people have died as a result of treacherous road conditions caused by the wintry weather, authorities told CNN.
The arctic blast isn't over just yet. Boston, New York, Philadelphia, Washington, Pittsburgh and Portland, Maine, among other parts of the Northeast, are expected to see freezing rain Monday.
Meteorologists say the freezing rain could reach as far south as North Carolina.
"These are all the areas where heavy rain will fall Sunday but then flash freezing will occur," CNN meteorologist Allison Chinchar explained. That means any puddles or standing water will freeze over, creating hazardous road conditions Monday morning.
The good news in all of this, however, is that after the winter storm clears, the National Weather Service says a "quieter weather pattern" is ahead.
Deadly weather-related crashes
Meanwhile, icy conditions have been blamed for several wrecks over the weekend.
At least three people were killed in a 67-vehilce crash on an icy stretch of I-95 in Baltimore, Maryland, Saturday morning. Lt. Kevin Ayd of the Maryland Transportation Authority Police told ABC News the number of vehicles involved in the crash could increase.
Emergency personnel responded to the scene and traffic was at a standstill for miles. Authorities urged stranded motorists to "remain warm and calm and shelter in place" while waiting for the wrecks to be cleared, Chief Roman Clark, a Baltimore Fire Department spokesman told CNN.
The cause of the crash is still under investigation, but Clark described the road conditions as "slippery."
Authorities in northern Virginia said they responded to more than 40 wrecks. One person was killed in a multi-vehicle wreck on I-495 in Fairfax County at 5:12 a.m. Saturday.
State police told CNN the man appeared to have been involved in a 23-vehicle wreck. The man's body was found on the shoulder of the interstate, approximately one mile north of the scene of the wreck.
Authorities in Oklahoma, Ohio, Indiana, Missouri and North Carolina all reported deadly wrecks that may have been weather-related.