A second burst of snow in three days is forecast Tuesday, potentially lengthening the weekend for schoolchildren one more day and clouding the morning commute.
Several inches of snow, with smaller chances of half a foot or slightly more, are forecast over a few hours starting after daybreak.
Forecasters and transportation officials cautioned that snow could accumulate at rates of an inch or two per hour, faster than snowplows can keep up with, in the midst of rush hour. If that is the case, officials urged drivers to delay travel or risk getting stuck.
"We really need people to have realistic expectations if the snow is falling anywhere close to the rate it fell [Sunday]," said State Highway Administration spokesman David Buck, explaining that it can take an hour for plow drivers to double back on their routes.
State highway officials were preparing to deploy about 1,900 workers and 1,700 vehicles to handle the snow, about the same number it used to handle Sunday's snows. While the highway administration received a lot of complaints about snowy roads Sunday, Buck urged people to be patient, as it takes crews four to six hours to clear roads after several inches of snowfall. The intensity of the snowfall Sunday, similar to what is expected Tuesday, makes that more difficult.
"It just takes a little time when it's snowing that hard," Buck said.
Tuesday's snow could be Baltimore's heaviest snowfall since Jan. 26, 2011, when 7.6 inches of snow was measured at Baltimore-Washington International Thurgood Marshall Airport. The airport received less than an inch of snow Sunday, but other areas reported significantly more accumulation.
The cleanup from Sunday's snow and an overnight coating of ice in areas around Baltimore stretching into Monday morning prompted Baltimore City and Baltimore, Carroll, Howard and Harford counties to close schools. Harford County Public Schools announced a two-hour delay for Tuesday, but no other decisions had been made as of Monday evening.
The Maryland Zoo in Baltimore closed Monday and decided to close Tuesday, "erring on the side of caution," spokeswoman Jane Ballentine said in an email.
Baltimore Gas and Electric Co. restored power to more than 22,000 customers Sunday and Monday, and it warned of more outages possible Tuesday.
Unlike Sunday's snow, which came from a massive storm that dumped ice and snow across the country, Tuesday's precipitation was expected to materialize as the result of a low-pressure system in the upper atmosphere and a burst of energy from speedy jet-stream winds over the region, said Amy Bettwy, a meteorologist with the National Weather Service's Baltimore/Washington forecast office in Sterling, Va.
"This one's just going to produce a narrow band of heavy snow from probably the central Appalachians up through southern New England," said Brian Edwards, a meteorologist with AccuWeather.com.
Weather Channel meteorologist Jim Cantore, who is known for showing up at the scenes of the nation's most extreme weather, said via Twitter that he planned to visit Baltimore in the morning to report on the snow.
Significant snowfall has been relatively rare in the Baltimore area since a record-setting 77 inches fell in winter 2009-2010. Only twice since then has snowfall surpassed 3 inches in any month — the January 2011 snowfall, another rush-hour storm remembered for stranding thousands of drivers during the evening commute, and a 3.2-inch storm last March 25.
Sunday's storm did nothing to end that streak because only 0.7 inches were measured at BWI, the point of record for Baltimore, even though 3 inches fell just a few miles on the other side of Interstate 95 in Columbia. Snowfall totals reached as much as 8 to 9 inches in northern Carroll, Baltimore and Harford counties.
The storm did bring snowfall across a wide swath of the country. Two-thirds of the surface of the continental United States was covered by snow as of Monday, the largest area since at least 2003, the most recent year for which data was available, according to the National Oceanic and Atmospheric Administration.
Arctic air was widespread, stretching from coast to coast. The temperature in Jordan, Mont., fell to 42 degrees below zero Saturday, the lowest U.S. temperature recorded during the storm.
The consequences of icy precipitation remained apparent across much of the country Monday, in some cases days after the storm passed.
More than 50 cars and trucks were caught in a series of chain-reaction crashes on the Pennsylvania Turnpike near Philadelphia on Sunday afternoon. One man was killed when he left his vehicle after the crashes, officials said.
More than 1,600 flights were canceled nationwide Monday, according to tracking website Flightaware.com, with "excessive delays" reported at Boston's Logan International, Chicago's O'Hare International, and Philadelphia International, among others.
At BWI, 19 outbound flights and six arriving flights were canceled Monday, according to FlightAware. Sixty flights to and from the airport were canceled Sunday.
About 650 travelers remained stranded overnight in the Dallas/Fort Worth International Airport overnight Sunday, officials said. That was an improvement from the more than 2,000 people who were forced to sleep on cots and chairs Saturday night and 4,000 people stranded in the airport on Friday night.
Any snow that falls Tuesday in Baltimore is likely to remain on the ground at least through the week. Frigid weather is forecast beyond the storm, possibly remaining below freezing from Tuesday night until Friday afternoon. Lows are forecast in the teens Tuesday and Wednesday nights, with highs in the mid-20s Wednesday and around freezing Thursday.
The pattern could change later this month, however. AccuWeather.com is forecasting higher-than-average temperatures in late December into early January, Edwards said.
Reuters contributed to this article.