Hurricane Sandy

Hurricane Sandy

Sandy was one of the most significant weather events in U.S. history and certainly near if not on top of the list for the Mid-Atlantic States. As of Friday November 2nd the U.S. death toll stands at 98, making Sandy the 4th or 5th deadliest tropical storm in Mid-Atlantic/New England history (and perhaps 3rd if the toll continues to rise). Here is a brief summary of the storms superlatives. Sorry, no graphics or photos with this blog, there are simply too many of these already in the ‘blogosphere’ and so I rest on words alone.

Size, Barometric Pressure, and Winds

Perhaps the most outstanding feature of Sandy from a meteorological point of view was its size and intensity. On Monday October 29th, just prior to making landfall in New Jersey, the storm had deepened to 940 mb—the lowest pressure ever observed in the mid-Atlantic and New England region of any tropical or extra-tropical cyclone in the region’s history. Atlantic City Airport measured a pressure of 948 mb (28.01”) when the storm made landfall late Monday. The only lower pressure yet measured on land north of Cape Hatteras was 947 mb (27.97”) at the Bellport Coast Guard Station on Long Island when the Great Hurricane of 1938 roared on shore.

A buoy (#ACYN4) just offshore of Atlantic City (about 500 feet from the end of the famous Steel Pier on the boardwalk) measured a pressure of 945.5 mb (27.92”).

Philadelphia smashed its old pressure record of 963 mb (28.43”) set in the previous “superstorm” of March 13, 1993 with a 953 mb (28.12”) reading at 9:32 p.m. Monday (October 29th).

Sandy’s circulation was enormous: about 1500 miles in diameter at its peak with tropical force winds extending out as far as 520 miles from its center at one point on Monday October 29th.

Given the storms size and intensity its maximum wind speeds reported were not actually all that impressive. A peak wind gust of 96 mph was reported from Eaton Neck, Long Island and 91 mph at Islip Airport on Long Island. The top sustained wind speed measured anywhere was ‘just’ 69 mph far away from the center in Westerly, Rhode Island (where peak gust of 86 mph was recorded). New Jersey’s peak wind gust was 90 mph at Tompkinsville. However, the duration of high winds and the enormity of the region enduring these was enough to cause tremendous damage even far away from the immediate coastline. Wind gusts to 60 mph were recorded in Gary, Indiana almost 800 miles from the storms center! It seems about half of the fatalities were caused by falling trees (including a former high school classmate of mine, William Sword, Jr. in Princeton, New Jersey).

If Sandy had been a tightly-wound storm as it came ashore with its pressure of 946 mb-the wind speeds in Atlantic City would have been those of a CAT 4 hurricane: sustained 131-154 mph. Atlantic City would now look like New Orleans or Mississippi after Hurricane Katrina made landfall back in 2005.

However, the meteorological statistics of Sandy pale in comparison to the damage it created.

Storm Surge and Waves

As is usually in the case of tropical storms, the worst damage was caused by the record storm surge that overwhelmed coastal New Jersey, New York City, and communities on the shores of Long Island and Long Island Sound. As all of you know by now, the 13.88’ tide level and 9’ storm surge at the Battery on the southern tip of Manhattan was unprecedented, which is saying a lot since the city has been recording storms and their flooding affects since the late 17th century. Jeff Masters mentioned in his blog on November 1st that the top surge and tide recorded anywhere in the storm was 9.45 feet and 14.60’ respectively at Bergen Point, New Jersey. Bergen Point is on the southern tip of Bayonne, New Jersey just north of Staten Island. Staten Island, a bureau of New York City, is now appearing to be the worst affected location by the storm.

The highest waves at sea measured by buoys were 32.5’ at the New York Harbor entrance about five miles east of Sandy Hook, New Jersey and 33.1’ at a buoy off the coast of Cape Hatteras, North Carolina. The highest shore waves are not known since they occurred after dark, but were probably in the 10-20’ range along New Jersey’s barrier islands.

Snowfall

Not since the ‘Snow Hurricane of 1804’ (see my blog of Nov. 3, 2010) has a tropical storm ended up producing so much snow at inland communities. Even some low elevation sites reported measurable snowfall like Huntington, West Virginia (elevation 564’) with 1.4”, an all-time October record. Higher up, phenomenal snowfall was measured including 18.1” at Elkins, West Virginia (elevation 1,926’) also an all-time October record. Peak amounts by state were:

36” Richwood, West Virginia

36” Newfound Gap, North Carolina

34” Mt. LeConte and Sevier, Tennessee

29” Redhouse and Oakland, Maryland

24” Norton, Virginia

14” Payne Gap, Kentucky

14” Laurel Summit, Pennsylvania (28” reported by the ski resort at Seven Springs)

3.5” Bellefontaine, Ohio

Warm air wrapping around the storm to the north of Pennsylvania precluded snowfall even at high elevations in New York and New England. In fact, a daily record high of 70° was recorded in Burlington, Vermont on October 30th while it was 27° and snowing in Hot Springs, Virginia!

Rainfall

There was a sharp line across New Jersey between areas that received heavy rainfall and those receiving little of such. Some locations in north Jersey received under .50” whereas in the southern portion of the state up to 9” fell. New York City (Central Park) had a storm total of only .95” whereas Atlantic City had an even 6.00”. Maryland reported the highest totals with the 12.55” at Easton leading the way. Widespread inland flooding, which was expected, failed too materialize.

Damage and Fatalities

It may be a while before the full extent of damage caused by Sandy is reckoned. As of the writing of this blog (Thursday November 1st) estimates seem to range between $20-60 billion. Given the economic destruction to New York City’s infrastructure, the high end of this range looks more likely and, I’ll bet, ultimately beyond the $60 billion figure. None of these figures mean much to the residents of Breezy Point in Queens, new York City where 110 homes burned to the ground or the thousands of residents who have lost their homes in New Jersey and other states.

Conclusion

As of now Hurricane Sandy is the 5th or 6th (if you include maritime fatalities) deadliest tropical storm to affect the mid-Atlantic or northeast regions of the U.S and the 2nd costliest in current dollar terms (with Katrina way ahead in this ignominious spot with $108 billion). Here are the contenders so far as fatalities are concerned for tropical storms in the region historically. I order them by land-based fatalities. This information is from HURDAT:

1. Great Hurricane of September 21, 1938: 256 fatalities on land (plus 382 at sea) total: 638

2. Hurricane Diane September 9-13, 1955: 184 fatalities on land

3. Tropical Storm Agnes June 20-21, 1972: 122 fatalities on land

4. Hurricane Sandy October 29-31: 96 fatalities on land (and still counting, plus at least 2 fatalities off-shore on the replica ship Bounty)

5. Hurricane Hazel October 14-15, 1954: 95 fatalities on land

6. Great 1944 Hurricane September 14-15, 1944: 64 fatalities on land, 326 at sea: 390 total

Hurricane Sandy will be studied for years to come. No storm of its like has been registered in the past 300 years of history in the region (at least since the first Europeans appeared on the shores of New York and New Jersey in the mid 17th century). It is a testament to the accuracy of forecasting techniques since there was no precedent to base forecasts on: the NWS fell back on its models. They were dead on accurate and their forecasts saved hundreds if not thousands of lives.

This gives us hope for future events of this magnitude. Let’s not forget that the climate models employed to forecast Sandy do not really differ in a significant way from those now used to forecast future climate change. The same science is behind them. It is simply a matter of magnitude vs. short-term versus long-term forecasts.

Christopher C. Burt
Weather Historian