Myriad Hazards Loom as Intense Snowstorm Moves In

A sprawling and formidable storm system will impact millions during the next several days, spreading snow, rain, wind, and coastal flooding from Chicago to Washington, D.C., and eventually up into Southern New England. The storm is already disrupting air travel at Chicago's O'Hare International Airport, one of the world's busiest, and threatens to knock out other hubs in the Washington, Philadelphia, New York, and Boston.

Storm total snowfall forecast from the National Weather Service Baltimore/Washington office.
Click on the image to enlarge. Credit: NWS.

The storm was expected to dump up to a foot of snow in Chicago on Tuesday, which would be the Windy City’s largest snowstorm of the year. Snow was also falling on Tuesday in parts of Minnesota, Iowa, Wisconsin, Indiana, Ohio, and will move into West Virginia by Tuesday evening.

From the Midwest, the storm will slide southeast and eventually coalesce into a powerful coastal storm to the east of the Virginia and Delaware coastlines by Wednesday. Computer-model projections show the coastal storm will rapidly intensify as it meanders to the east-northeast, blasting the vulnerable Delaware and New Jersey shorelines with high winds and battering waves, while dumping as much as 30 inches of snow in the higher elevations to the southwest and west of the nation's capital.

In Washington, D.C., a city known for all but shutting down when snow is merely mentioned by weather forecasters, projections call for about 6-to-10 inches of snow, possibly more, depending on precipitation rates and surface temperatures. The heaviest snowfall amounts should fall in the western part of the D.C. metro area, with warmer air limiting accumulations to the east of Interstate 95.

If more than 2 inches of snow falls, then Washington will end its longest streak on record without a snowstorm of 2 inches or more. The last time that occurred was on Jan. 26, 2011, when 5 inches fell.

The Washington Post’s Capital Weather Gang blog has nicknamed the storm “snowquester,” since it comes in the first week of the automatic federal budget cuts known as the “sequester.” Meanwhile, the Weather Channel has named the storm “Saturn,” setting up a naming duel for the largest share of the social media conversation in the Mid-Atlantic.

Simulated radar for Wednesday, showing heavy precipitation falling in the Mid-Atlantic states as the storm intensifies.
Click on the image to enlarge. Credit:

The areas likely to see the most snow are in the higher elevations of West Virginia, Virginia, and Maryland, with crippling amounts of heavy, wet snow that are likely to cause power outages. Outages are also likely to occur in more urban areas closer to D.C., Baltimore, Philadelphia, New York City, and possibly Boston, due to the combination of high winds and heavy wet snow.

The most likely period for accumulating snow in New York and Philadelphia will come on Wednesday night into Thursday morning, and in southern New England from Thursday through Friday.

By the time the storm swirls out to see late in the week, it may have caused widespread power outages and stranded travelers at airports from Chicago to D.C. to New York and Boston. 

The storm also poses a formidable coastal flooding threat to the vulnerable New Jersey coast. The National Weather Service office in Philadelphia warned of the potential for “major coastal flooding” to take place along the Jersey shoreline, which was severely damaged during Hurricane Sandy in October 2012. Fortunately, astronomical tides are not running particularly high, which should limit the flooding potential somewhat, but an extended period of strong, onshore winds — which may gust as high as 60 mph at times — still pose a significant danger.

The National Weather Service said that moderate to major tidal flooding is expected along the Atlantic Coast, Delaware Bay, and Raritan Bay. The greatest flooding threat will come with the Wednesday afternoon and late Wednesday night high tides, NWS said in the online briefing.

Ominous Weather Pattern

The storm is taking shape amid a weather pattern that is eerily reminiscent of conditions that have given rise to other extreme coastal storms, with the jet stream expected to carve out a deep dip, or trough, of low pressure off the Mid-Atlantic coast that will be all but trapped by a strong high pressure area north of New England and a so-called “blocking pattern” over northeast Canada and Greenland. The blocking means that the storm is likely to slow its forward motion as it moves up the coast, and some computer models show it lingering off Cape Cod for about two days, which would bring more damaging impacts to southeastern New England.

Blocking patterns are a key ingredient in major East Coast storms, and a formidable block was in place when Hurricane Sandy roared ashore in New Jersey in October.

An aerial view of damage to the town of Mantaloking, N.J., from Hurricane Sandy in October. The Jersey Shore is now far more vulnerable to damage from coastal storms as a result of Sandy. 
Click on the image to enlarge. Credit: USGS.

Some studies have shown potential links between rapid Arctic warming and its associated sea ice loss and an increase in blocking patterns in the Northern Hemisphere, although other researchers working in this field say there have not been statistically significant increases in blocking patterns

Blocking patterns have been linked to several noteworthy extreme weather events, such as the deadly 2010 Russian heat wave and Pakistan floods, the 2003 European heat wave, and the March heat wave of 2012 in the U.S.

The 2012 sea ice melt season was extreme, with sea ice extent, volume, and other measures all hitting record lows. The loss of sea ice opens large expanses of open water, which then absorbs more of the incoming solar energy and adds heat and moisture to the atmosphere, thereby helping to alter weather patterns. Exactly how sub-Arctic weather patterns are changing as a result, however, is a subject of active research.

In addition to the research into how the Arctic may be affecting extreme weather events, other studies show that manmade global warming is adding more moisture to the atmosphere, resulting in more precipitation extremes throughout the Northern Hemisphere.

Scientists expect that major snowstorms will continue to occur as the climate warms, in part because warmer air and ocean temperatures will increase the amount of water vapor in the atmosphere. That added water vapor could fuel unusually heavy snowstorms, such as the blizzard that buried parts of New England under 40 inches of snow in early February.

Recent observations do show more frequent heavy precipitation falling in many areas, although it has not been the case in every region of the U.S. and season.

A forthcoming paper in the Bulletin of the American Meteorological Society found there were more than twice the number of extreme regional snowstorms from 1961-2010 in the U.S. as there were in the previous 60 years.

“The greater number of extreme storms in recent decades is consistent with other findings of recent increases in heavier and more widespread snowstorms,” the study said.    

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