Snow was tapering off by late morning in Baltimore and points north and west, expected to end with 3-6 inches of accumulation around the region. A blast of cold air was meanwhile moving in behind the storm.
Snowfall totals included 5.5 inches in Westminster, 5 inches in Owings Mills and Hunt Valley, 4.7 inches near Perry Hall and 4 inches near Columbia and in Northeast Baltimore's Hamilton neighborhood, according to the National Weather Service. Ice accumulated to as much as a tenth of an inch around the region overnight before precipitation turned to snow, according to the weather service.
While snow totals did not meet expectations of as much as 8-10 inches, frigid temperatures were surpassing forecasts as they dove into the teens. Baltimore-Washington International Thurgood Marshall Airport dropped to 16 degrees by 10 a.m. and was hovering around 17 degrees at noon. Temperatures were expected to fall, with wind gusts making it feel as cold as the single digits.
Lows were forecast in the single digits Monday night into Tuesday morning, possibly threatening a record low of 5 degrees set in 1873, Baltimore's coldest reading ever in March.
The winter storm brought snow and then frigid wind chills across 1,500 miles, from Colorado to Massachusetts. The heaviest snow in the mid-Atlantic was forecast across central Virginia and into Southern Maryland.
In the Baltimore region, the snow forecast was enough to cancel schools, with most announcements made Sunday night. The federal government closed its offices, and attractions including the National Aquarium and Maryland Zoo also closed. Baltimore City Council canceled its meeting scheduled for Monday night.
"Everyone in Maryland is a little snow-weary at this point," said Anne Arundel County Executive Laura Neuman. "But we're focused as if this was the first storm of the season."
Neuman said she sent out an email over the weekend: "I said I know it's March and everyone's ready for spring, but this could be the worst storm of the season."
The Maryland State Highway Administration said it and the Maryland Transportation Authority had a combined 2,600 pieces of equipment on the roads salting and plowing, and urged Maryland residents to stay off the roads if possible.
Baltimore transportation director William Johnson said rainfall Sunday night prevented crews from pre-treating roads, because it would have been washed away. But by midday, city crews had cleared major roadways, he said.
"We still have significant work yet to be done on the neighborhood streets," he said.
Mayor Stephanie Rawlings-Blake said this winter has been "brutal" and urged residents to check on elderly neighbors and others who may be having difficulty.
"It's been a relentless winter, and it calls on us to really step up and come together as a community," the mayor said. "My request to the citizens is to really do what you can to be neighborly."
The ice and snow forced flight delays and cancellations throughout the region Monday, according to FlightAware.com, which tracks delays and cancellations across the country. Airports from Washington north through Baltimore and Philadelphia and into the New York region were seeing the worst cancellations of the day.
At BWI Thurgood Marshall Airport, more than 130 departing flights were cancelled as of 10:30 a.m., about 45 percent of those scheduled. At Washington Dulles International Airport, a fourth of flights -- more than 100 -- were cancelled, and nearly 300 departing flights were canceled at Ronald Reagan Washington National Airport, representing 65 percent of those scheduled.
A few dozen flights were also delayed at the three airports.
The Maryland Transit Administration cancelled all MARC train and commuter bus service for Monday, after the federal government announced closures. There were also diversions on bus lines throughout Baltimore, and Charm City Circulator bus service was suspended. Amtrak was running trains at reduced frequencies along its Northeast Corridor.
Baltimore Gas and Electric Co. reported only a few dozen power outages across the region.
Temperatures were expected to stay below freezing through Wednesday afternoon, with highs in the upper 20s and lows in the teens Tuesday, and highs in the mid-30s and lows in the mid-20s Wednesday, with skies clearing.
Baltimore Sun reporters Kevin Rector, Alison Knezevich and Pamela Wood and Reuters contributed to this report.