Guide to Interpreting Local Forecasts
When the forecast calls for snow or ice, here's what you can generally expect from your
D.C. Government Snow Team
0 - 4 Inches - Winter Weather Advisory
4 - 8 Inches - Winter Storm Warning
8 - 12 Inches - Winter Storm Warning
12 - 18 Inches - Winter Snow Warning or Blizzard Warning
18 - 24 Inches - Blizzard Warning
Freezing Rain or Ice - Winter Weather Advisory for Freezing Rain or Ice
04 Inches
WINTER WEATHER ADVISORY
Slippery roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Less than 2 inches: salting completed within 4 hours after the end of each storm.
Over 2 inches: continuous plowing and salting. Plowing to bare pavement completed up to 12
hours after end of storm.
RESIDENTIAL STREETS
Less than 2 inches: salting where needed, completed within 12 hours after end of storm.
Over 2 inches: plowing begins as needed, up to 12 hours after the end of storm. Plowing
completed up to 24 hours after end of stone.
BUS AND RAIL ROUTES
Metrorail: normal operations
Metrobus: normal operations
Metro Access: normal operations
Metro Parking: 5% fewer spaces
Transit Buses: normal operations
VRE & MARC: normal operations
48 Inches
WINTER STORM WARNING
Some Hazardous Roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Continuous plowing. Through lanes plowed to bare pavement up to 12 hours after end of
storm.
RESIDENTIAL STREETS
Plowing begins up to 12 hours after storm ends. Streets passable* up to 24-36 hours after
end of storm.
BUS AND RAIL ROUTES
Metrorail: normal operations
Metrobus: detours around hilly areas, with delays
Metro Access: some delays
Metro Parking: 10% fewer spaces
Transit Buses: service on snow routes only, minor delays
VRE & MARC: normal operations
812 Inches
WINTER STORM WARNING }
Hazardous roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Continuous plowing. Through lanes plowed to bare pavement up to 24 hours after end of
storm.
RESIDENTIAL STREETS
Plowing begins up to 24 hours after end of storm. Streets made passable* (but not cleared
to bare pavement) up to 48 hours later.
BUS AND RAIL ROUTES
Metrorail: six-car trains, delays between trains
Metrobus: service on snow routes only; major delays
Metro Access: very limited service; major delays
Metro Parking: 25% fewer spaces
Transit Buses: service on snow routes only; minor delays
VRE & MARC: modified schedule, reduced service, delays
1218 Inches
WINTER STORM WARNING OR BLIZZARD WARNING
Hazardous Roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Through lanes plowed to bare pavement up to 24-36 hours after storm ends. Expect narrowed
and/or blocked lanes due to accumulations.
RESIDENTIAL STREETS
Plowing begins up to 36-48 hours after storm ends. One lane will be made passable* 2-3
days later. Expect snow-packed roads.
BUS AND RAIL ROUTES
Metrorail: six-car trains only; major delays between trains
Metrobus: limited service on snow routes
Metro Access: very limited service; major delays
Metro Parking: 40% fewer spaces
Transit Buses: service on snow routes only; major delays
VRE & MARC: modified schedule, reduced service, delays
1824 Inches
BLIZZARD WARNING
Treacherous roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Through lanes plowed to bare pavement up to 36-48 hours after storm ends. Narrowed and/or
blocked lanes due to heavy accumulations.
RESIDENTIAL STREETS
Plowing begins 48 hours after storm ends. One lane will be made passable* 2-4 days later.
Some roads may be impassable for longer periods. Expect snow-packed roads.
BUS AND RAIL ROUTES
Metrorail: limited service above-ground. If only underground service, it is limited to
Red: Grosvenor to Union Station; Blue: Rosslyn to Stadium Armory; Orange: Ballston to
Stadium Armory; Yellow: L'Enfant Plaza to Mt. Vernon Square/UDC; Green: U St. to
Anacostia.
Metrobus: limited service on snow routes only; major delays
Metro Access: very limited service
Metro Parking: 60% fewer spaces
Transit Buses: limited service on snow routes
VRE & MARC: modified schedule, reduced service, delays
Freezing Rain or Ice
WINTER WEATHER ADVISORY FOR FREEZING RAIN OR ICE
Very Treacherous Roads!
MAJOR ROADS AND HILLY NEIGHBORHOOD STREETS
Continuous salting and/or sanding until road conditions improve. Bridges, ramps,
underpasses freeze first. Possible traffic signal outages and tree limbs in roadway.
RESIDENTIAL STREETS
Salting begins up to 24 hours after storm ends as needed. Possible traffic signal outages
and tree limbs in roadway.
BUS AND RAIL ROUTES
Metrorail: expect delays at above-ground stations
Metrobus: normal service depends on severity of road conditions
Metro Access: normal service depends on severity of road conditions
Metro Parking: 5% fewer spaces
Transit Buses: normal service depends on severity of road conditions
VRE & MARC: normal operations
*Passable means that the roads will be snow packed, only one travel lane will be
salted and/or plowed, and all-weather tires are a must. |