The Size Of Hurricane Sandy – How Does It Compare?

Hurricane Sandy became  a very large tropical cyclone as it morphed into a hybrid large low pressure system. The figure above from our book

Pielke, R.A., Jr. and R.A. Pielke, Sr., 1997: Hurricanes: Their nature and impacts  on society. John Wiley and Sons, England, 279 pp. Hurricane Sandy provides examples of sizes of tropical cyclones that occurred in the past. The largest, Tip in 1979, was from the western North Pacific Ocean.

The size of Sandy, as reported by the National hurricane Center, is given for two time periods late in its lifetime below.

1100 AM EDT SUN OCT 28 2012

MAXIMUM SUSTAINED WINDS…75 MPH…120 KM/H
PRESENT MOVEMENT…NE OR 45 DEGREES AT 14 MPH…22 KM/H
MINIMUM CENTRAL PRESSURE…951 MB…28.08 INCHES

HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 175 MILES…280 KM…FROM
THE CENTER…AND TROPICAL-STORM-FORCE WINDS EXTEND OUTWARD UP TO 520
MILES…835 KM.

1100 AM EDT MON OCT 29 2012

MAXIMUM SUSTAINED WINDS…90 MPH…150 KM/H
PRESENT MOVEMENT…NNW OR 330 DEGREES AT 18 MPH…30 KM/H
MINIMUM CENTRAL PRESSURE…943 MB…27.85 INCHES

HURRICANE-FORCE WINDS EXTEND OUTWARD UP TO 175 MILES…280 KM…
MAINLY SOUTHWEST OF THE CENTER…AND TROPICAL-STORM-FORCE WINDS
EXTEND OUTWARD UP TO 485 MILES…780 KM.

For comparison with the figure from the book, the distance between 5 degrees of latitude in the figure below is 555 km (300 nautical miles or 345 statute miles ).  Tip had tropical storm winds out to ~700km on the east side and  hurricane winds out to about ~175 km from the eye.

The  analyses from NHC [shown below] show that Sandy’s size of tropical storm and hurricane winds were comparable to Tip, but, fortunately, the hurricane winds were much less in Sandy.  Also, the radius of hurricane winds, appears to have contracted substantially at and right after landfall.

Clearly, Sandy was a giant tropical cyclone, and rivals the largest ones in size that occur in the Pacific Ocean. A major difference with Tip, however, is that Tip attained wind speeds of up to 190 mph (305 km/h) and a central pressure of 870 millibars (25.69 inches of mercury) – see, while Sandy was a much more modest hurricane.  This suggests the potential that if a major hurricane (such as Hazel from 1955) followed the same path as Sandy as it merged with a midlatitude storm system, a truly worse-case superstorm could occur.  Thus the worse-case scenario, even with the current climate, did not happen with Sandy.

Regardless, how, or if, the risk from hurricane landfalls of this type increases in the future, a prudent policy path would be to reduce the risk from all plausible hurricane landfalls. through more effective land use planning.