Cornell Quigley helps guide a Fairfax County school bus to turn around after it was unable to make it up a hill on Jan. 6, 2015, in Reston, Va. (Photo by Jahi Chikwendiu/The Washigton Post) (Jahi Chikwendiu/The Washington Post)

Most major school systems in the Washington area have announced that they will close schools on Friday in advance of a storm that threatens to bring more than two feet of snow to the region.

School officials in Alexandria, Arlington, Fairfax, Loudoun, Montgomery and Prince William counties have announced they will close schools Friday, and Mayor Muriel Bowser said that D.C. Public Schools also will shut down Friday. A Prince George’s spokeswoman said classes are not in session Friday because it is a previously scheduled grading and planning day for teachers, and schools and offices will close at noon.

Nearly all large Washington area school systems made the decision to delay start times, if not cancel classes altogether Thursday because of hazardous road conditions, but some did not make the call until just hours before classes were supposed to start.

[Weather closures in the D.C. area for Jan. 22]

The decisions to delay or cancel school came after about an inch of snow on untreated roads wrought havoc on commuters Wednesday evening and left many roads — unreachable because of the gridlock — slick with ice Thursday morning. The traffic mess raised anxiety over how the region will handle a historic snowstorm that is expected to bring as much as two feet of snow to the region beginning Friday afternoon or evening.

D.C. Mayor Muriel Bowser updates residents on the city's response plan and school closings ahead of the massive snow storm expected to hit the area as early as Friday. (WUSA9)

It is often a difficult call for school systems to make when they decide to delay or cancel on a given day, with educators concerned about keeping students on track academically while maintaining safety. Many school officials last year ended up apologizing to parents after keeping schools open on a day when snowfall during morning rush hour left buses stuck.

[From 2015: many of region’s schools opened in storm, drawing ire]

The Fairfax County school system, one of the nation’s largest, and Alexandria city schools announced Wednesday night that they would delay classes before deciding to cancel classes altogether early Thursday. Prince William County schools, which cover a wide swath of Northern Virginia that includes some rural roads, made the call to cancel classes Wednesday night. D.C. Public Schools and Montgomery County schools in Maryland opted for two-hour delays, making the call early Thursday morning. Prince George’s County schools decided to close.

Loudoun County Public Schools opened on time. Spokesman Wayde Byard said the county received a relatively light dusting of snow.

District Mayor Muriel E. Bowser (D) apologized Thursday at a news conference for the city’s response to Wednesday night’s snow and the poor road conditions

“We are very sorry for the inadequate response,” she said. “We did not provide adequate resources at a time when it could have made a difference with the commute.”

Bowser declared a state of emergency and a snow emergency for the city in advance of the Friday storm. She said schools in the District will be closed Friday — the first school district in the region to announce a closure ahead of the storm. The University of Maryland in College Park announced Wednesday night that it will close Friday through Sunday, ahead of the next semester, which is slated to begin Monday.

Capital Weather Gang's Angela Fritz has your forecast and snow accumulation predictions as D.C. enters a state of emergency in response to a major storm heading toward the District and the Mid-Atlantic region. (Ashleigh Joplin,Angela Fritz/The Washington Post)

[See school closings for Friday, ahead of the expected blizzard]

Arlington Public Schools Superintendent Patrick Murphy made the call at around 4:15 a.m. to cancel classes because of slick road conditions, said Assistant Superintendent Linda Erdos. Text messages and emails began going out to parents shortly thereafter, though some did not receive them until 5:15 a.m.

Erdos said Murphy and school transportation staff conferred with county public works officials throughout the night and learned that many residential streets remained icy because public works crews were unable to get to them to treat them because of Wednesday night’s gridlock.

Erdos said she and other school officials feared buses would not be able to maneuver safely or would get stuck.

“It really was a safety issue for children,” Erdos said.

As for Friday, Erdos said school officials are keeping a close eye on forecasts to see when the blizzard would start. Even an afternoon snowfall start — which could imperil buses attempting to maneuver down narrow residential streets — could mean canceling school. But if the snow is expected to hold off until evening, she said, classes likely would go on as normal.

D.C. Public Schools began notifying parents by 5 a.m. that it would delay start times by two hours. School spokeswoman Michelle Lerner said the system typically makes its decisions between 4 a.m. and 5 a.m., based on factors including temperature and wind chill, levels of snow and ice, road conditions and the availability of public transit. Also important is the forecast for the day ahead. The mayor makes the final call about opening, delaying or closing schools.

Prince George’s County school officials decided on a two-hour delay for Thursday at about 4:30 a.m. and then to close the school system at 7 a.m. They said it’s well known in the region that road and weather conditions can change dramatically in short order.

Monica Goldson, chief operating officer, said the school system followed its typical protocols for weather closures and delays, assessing road and weather conditions across the county.

“When our team determined traffic conditions on major roadways were still severe, we changed the status,” Goldson said in a statement. “We have to take into account considerations like bus stop wait times, conditions of both neighborhood and major roads and current weather conditions and determined it was best to have our students at home today. We were hopeful that the late arrival would yield better road conditions, but unfortunately did not.”

In Montgomery County, the decision to close schools came at 4:30 a.m., following a process that began at 2:30 a.m., when a designated “snow team” of transportation staff started driving county roads, checking forecasts and consulting with other school systems.

The two-hour delay was posted online and went out through television, Twitter and email, shortly after 4:35 a.m.

Montgomery schools spokesman Derek Turner said the district took into account the traffic chaos of Wednesday night. “Certainly we were looking at that as it was happening and thinking about how it would apply in the morning,” he said.

But the district makes its decision based on the most timely information it has in the morning, he said. On Thursday, the district decided that, with a two-hour delay, it was safe to open schools.

“Everyone wants to know as soon as possible, but we want to make sure we’re making a careful and thoughtful decision,” he said

Hours later, on Thursday afternoon, Montgomery officials broke with the usual practice of deciding school closings in the early-morning hours, announcing schools would be closed Friday, Saturday and Sunday. The district considered factors including weather forecasts, other school system closures and Maryland Gov. Larry Hogan’s declaration of a state of emergency, to begin at 7 a.m. Friday. “All of those playing together,” said Montgomery schools spokesman Derek Turner.

On Monday, Montgomery students are off school because of a previously scheduled professional day for teachers.

Dana Hedgpeth contributed to this report.

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