In a winter that has produced record-high temperatures and springlike days, Baltimore residents prepared Monday for an overnight storm expected to blanket the Mid-Atlantic with the highest snow totals of the season.
More than 100 flights at BWI Thurgood Marshall Airport were canceled, some schools and colleges announced Tuesday closures and the University of Maryland men's basketball team left town early for its NCAA tournament debut — all in advance of a nor'easter expected to drop four to eight inches of snow in Baltimore and as much as a foot or more in suburbs to the north and west.
Gov. Larry Hogan declared a state of emergency beginning at 9 p.m. on Monday, which will allow the state to more quickly mobilize resources.
"Certainly it's going to be, by far, the biggest storm of the year," said Ray Martin, a National Weather Service meteorologist.
That's not saying much in a winter that's delivered less than an inch of snow so far. Still, a winter storm warning went into effect Monday evening and was expected to last until 2 p.m. Tuesday.
Forecasters expected low-pressure areas over Missouri and off the northern Florida coast to come together over the Mid-Atlantic overnight. A combination of polar air and Gulf of Mexico moisture was predicted to create a storm moving through Maryland and continuing northeast, bringing heavy snow from Pennsylvania to Maine and into eastern Canada.
Snowfall totals as high as 20 inches were expected in New York City, and the National Weather Service warned that blizzard conditions with wind gusts over 35 mph and low visibility would extend from the Philadelphia area to Maine. About 5,000 Tuesday flights within, into or out of the United States were already canceled late Monday, according to flightaware.com. Amtrak modified service up and down the Northeast Corridor.
Weather models Monday showed a range of possible outcomes for Baltimore and the Interstate 95 corridor, depending on where the line between snow and a wintry mix with sleet and rain set up overnight.
Hogan urged Marylanders to get prepared and stay safe. He warned the storm could bring power outages and treacherous driving.
"Some people are sort of lulled into a false sense of security because we've had this great 70-degree weather and everybody thinks it's springtime and we're ready to put on the flip-flops and go barbecue in the backyard," the governor said.
"This is a serious winter storm," he said.
The University of Maryland, College Park, Towson University and McDaniel College in Westminster announced they would close Tuesday, as did public schools in Baltimore City and Carroll, Howard, Anne Arundel, Baltimore and Harford counties.
(For information about school delays and closings, go to bsun.md/snowday.)
Greg Slater of the State Highway Administration said crews would work through the night to keep roads clear and asked people to stay home Tuesday if possible.
The agency has 2,700 workers and the same number of pieces of equipment on hand to battle the snow, he said. The state had about 380,000 pounds of salt and 1 million gallons of salt brine available for this storm.
In Baltimore, officials activated the snow emergency operations center and called into service 180 pieces of heavy equipment to prepare for the storm, city Transportation Department spokeswoman Adrienne Barnes said.
The city planned to call contractors in at midnight to join city crews, she said.
Officials asked commuters to avoid driving Tuesday morning for safety reasons and to give snow-removal crews room to do their jobs. Barnes asked people to exercise "extreme caution" when deciding whether to drive.
"If you don't have to go out tomorrow, you might want to stay indoors," she said.
The Maryland Transit Administration said commuter buses and its mobility/paratransit service would be suspended Tuesday. MARC trains will be on a reduced "R" schedule. "Ice trains" will run on the light rail system to keep ice from forming on the line.
Local buses were set to run on schedule — though officials said diversions were possible.
In Anne Arundel County, libraries announced they would be closed Tuesday. In Carroll County — where forecasts predicted a foot or more of snow — government offices will be closed, and Carroll Hospital Center canceled community programs and support groups.
Carroll was expecting snow and sleet accumulation of five to nine inches overnight and possibly another four to eight inches Tuesday. Jeff Castonguay, the county's public works director, said he hoped to get plows through major roads and initial routes by the start of the morning commute, but acknowledged, "It could be a little dicey for a while."
The Maryland Zoo in Baltimore announced it would close Tuesday as well. Spokeswoman Jane Ballentine said most of the animals will be kept inside during the storm, and said the zoo ordered extra food in case roads are shut down.
"It seems that everyone is going to be closed in tightly," Ballentine said. "We're going to have folks keeping track of stuff through the night."
Stadium parking lots at Oriole Park at Camden Yards and M&T Bank Stadium, which were used for snow dumping after the whopping 29.2-inch blizzard last year, were not expected to be needed for that purpose this year, Stadium Authority spokesman Michael Frenz said.
The stadium authority has an agreement with the city to allow people to park in the lots if snow emergency routes are activated, he said.
Jonathan Dean, a spokesman for BWI, said crews would work overnight to keep runways clear. More flight cancellations are expected, he said, especially since the storm will be hitting other parts of the Northeast.
Maryland State Police troopers in several units not normally assigned to road patrol were put on storm duty to aid other agencies in their snow response, officials said.
In Towson, Vince Ayd of Ayd Hardware anticipated the snow with a slightly different perspective. Ayd put his inventory of ice melt away for the season two weeks ago, replacing it on the shelves with grass seed.
On Monday it was back out again, and Ayd said he hoped for a boost in the sale of winter-related supplies — down about 50 percent compared to last year.
"This may be our one and only big one," Ayd said. "I'm grateful for it."
March snowfall is relatively common in Maryland, but is less likely than January or February snow because even if temperatures drop below freezing, the sun's rays are more intense as spring and summer approach.
The Palm Sunday storm of March 28-29, 1942, holds the record for Baltimore's biggest March snowfall, with a surprise 22 inches. Another storm dropped 10.5 inches March 2-4, 1960.
More recently, a March 1993 storm spawned tornadoes in the Southeast and snow across the Northeast, including 11.3 inches in Baltimore.
Baltimore received more than 20 inches of snow in total during March 1960 and in March 1892. More than 14 inches fell over both March 1937 and 1943.
At least a few inches of snow have fallen in March for four straight years, since 2013, including a foot in March 2014.
Baltimore Sun reporters Erin Cox, Ian Duncan, Rachael Pacella, Emily Chappell and Jacob deNobel, and the Associated Press contributed to this article.