As people across the eastern United States prepare for this weekend's winter storm, here's what we know:
WHAT IS IT? "A potentially crippling winter storm,'' according to the National Weather Service, which forecasts heavy snow and high winds across the northern mid-Atlantic region, including Baltimore, Washington, Philadelphia and New York City.
WHY NOW? All the ingredients have come together to create a blizzard with brutally high winds, dangerous inland flooding, white-out conditions and even the possibility of thunder snow, with Washington squarely in the bulls-eye, forecasters said. The storm initially picked up warm water from the Gulf of Mexico, then gained much more moisture from the warmer-than-usual Gulf Stream off the East Coast.
SHOULD WE WORRY? A blizzard warning has been issued for the D.C. area from 3 p.m. Friday until 6 a.m. Sunday, meaning a snowstorm with winds exceeding 35 mph is expected. Winds reaching up to 50 mph are possible, which would reduce visibility to zero. Power outages and coastal flooding are expected.
HOW MUCH SNOW? Storm Team4 is expecting 20 to 30 inches of snow during this storm -- and that range would put this storm firmly in the top five biggest snowfalls of all time for the region.
WHEN'S THE WORST? The storm has already brought freezing rain, ice and snow to Arkansas, Tennessee and Kentucky. The heavy snow should begin falling Friday afternoon in Washington, and keep falling into Sunday as it moves up the coast.
HOW LONG? Washingtonians expected the snow to arrive Friday afternoon and continue into Sunday as the slow-moving storm moves up the coast. Snow may fall for 36 hours straight, meaning you may need to stay wherever you sleep Friday.
Washington, D.C., Maryland and Virginia local news, events and information
Even President Barack Obama's motorcade was stuck in traffic. According to White House pool reports, Obama was driven by car from Joint Base Andrews in Maryland to the White House after bad weather grounded helicopters. A drive that usually takes 25 minutes took more than an hour, reports said. Vehicles in the president's motorcade skipped and slid, making contact with curbs. White House reporters spotted at least three crashes along the way.
WHO HAS DECLARED A STATE OF EMERGENCY? Leaders in D.C., Maryland and Virginia declared states of emergency on Thursday. Virginia Gov. Terry McAuliffe declared the state of emergency Thursday morning. The declaration authorizes state agencies to assist local governments in response to the storm. A state of emergency went into effect in Maryland at 7 a.m. Friday. The Maryland National Guard will be on standby, Gov. Larry Hogan said.
A snow emergency went into effect in the District at 9:30 a.m. Friday. A snow emergency allows transportation workers to clear snow emergency routes curb to curb. Violators face a $250 ticket, a $100 tow and a $25-per-day fee until they pick up their vehicles.
WHAT DO I NEED? Grab lots of warm clothing and blankets, batteries and flashlights. You should also have a first aid kit ready. Click here for a list of 15 things you should do before the snow arrives.
WHAT TO DO? STAY INSIDE! Authorities pleaded with people to hunker down by 3 p.m. Friday and stay there until the storm is over.
HOW CAN I HELP OTHERS? Be on the lookout for homeless people, who need shelter from the storm. If you see someone in the D.C. area who needs shelter or warmer clothing, call the following numbers:
- The District: 202-399-7093 or 311 if calling within the city
- Arlington County: 703-228-1010 (24 hours)
- Fairfax County: 703-691-2131 (police non-emergency line)
- Montgomery County: 311 if calling within the county
- Prince George's County: 888-731-0999