A "super cold" blast locked much of the country in ice Tuesday, stranding thousands of motorists, canceling some Mardi Gras festivities and collapsing the roof of a Kentucky store.
The latest arctic weather system to hit the winter-weary eastern U.S. set or tied record March lows in Baltimore, Scranton, Pa., Morgantown, W.Va., Zanesville, Ohio, and Flint, Mich. Thousands of motorists were stranded on Arkansas interstates and slept in their cars and trucks overnight.
The cold front extended from the Canadian border to southern Texas. Single-digit temperatures Tuesday made for a chilly morning commute: Baltimore, where the mercury rose to only 4 degrees early Tuesday, shattered a hundred-year record.
Accumulated ice and snow were believed to have collapsed the roof of a Dollar General store in Mayfield, Ky., on Tuesday afternoon, authorities said. The roof — originally 9 feet high — fell 3 feet in some places when it gave way about 1:30 p.m. ET, City Planner Brad Rodgers said.
Ice and accidents stalled traffic so badly on Interstates 55 and 40 in Arkansas that thousands of motorists slept in their cars overnight.
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"People have been stopped over 14 hours without moving an inch on this treacherous highway," one of them, Sandy Shute, wrote in an email Tuesday to NBC station WMC of Memphis, Tenn. "People have run out of gas, my husband is trapped, very cold and he has no heat."
James Metzelaars told the station that he was among those forced to camp out overnight.
"I sat there for 3½ hours and traveled three miles," he said.
Drivers slid off the road on Highway 150 in Guilford County in central North Carolina, snarling traffic in both directions.
In Louisiana, Mardi Gras revelers woke up (or just kept partying) to ice and sleet Tuesday morning. Interstate 10 was closed for almost 60 miles for several hours between Lafayette and Lake Charles, and some Mardi Gras events were canceled in both cities.
Ice cover on the Great Lakes reached 90.5 percent — the most in 19 years and the third-highest on record — according to the Great Lakes Environmental Research Laboratory. With frigid temperatures persisting, the record of 95 percent could be surpassed before the spring thaw, the National Oceanographic and Atmospheric Administration said.
In southern Texas, more than 7,100 customers remained without power in the Houston area Tuesday afternoon, CenterPoint Energy reported.
The Kentucky Transportation Department, meanwhile, warned drivers that the majority of all roads in the state were covered with snow and ice.
The frigid storm from out West — which downed power lines and snarled Midwest travel earlier — was blamed for at least seven traffic-related deaths across an icy arc stretching from the Mississippi Valley up the Atlantic Coast.
The storm also hammered air traffic, with nearly 8,000 flights canceled or delayed Monday and 832 canceled along with 3,903 delayed Tuesday, according to the tracking site FlightAware.com
In Michigan, a Coast Guard cutter based in Detroit made its way to Lake St. Clair on Tuesday to rescue an injured dog that was stranded on the ice. The dog, which had severely injured its paws trying to dig a barrier in the ice, was airlifted to safety aboard the Bristol Bay and taken to a shelter for food and treatment, the Coast Guard said.
Elizabeth Chuck of NBC News contributed to this report.