Skip to main content

Why is Sandy unusual?

By David Nolan, Special to CNN
October 30, 2012 -- Updated 0246 GMT (1046 HKT)
Atlantic City, New Jersey, resident Kim Johnson inspects the area around her apartment building, which flooded on Tuesday, October 30. Large sections of an old boardwalk also were destroyed by Superstorm Sandy. Nearly 11,000 people spent Monday night in 258 Red Cross-operated shelters across 16 states because of Sandy, the American Red Cross tells CNN.<strong> </strong><strong><a href='http://www.cnn.com/2012/10/30/us/gallery/ny-sandy/index.html'>View photos of New York recovering from impact</a></strong><strong>.</strong> Atlantic City, New Jersey, resident Kim Johnson inspects the area around her apartment building, which flooded on Tuesday, October 30. Large sections of an old boardwalk also were destroyed by Superstorm Sandy. Nearly 11,000 people spent Monday night in 258 Red Cross-operated shelters across 16 states because of Sandy, the American Red Cross tells CNN. View photos of New York recovering from impact.
HIDE CAPTION
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
Sandy's destructive path
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
>
>>
STORY HIGHLIGHTS
  • David Nolan: As far as hurricanes go, the storm we call "Sandy" is not very intense
  • Nolan: There are two elements that make Sandy unusual, possibly even "super"
  • He says Sandy's right-to-left pathway is atypical, as is its intact hurricane core
  • Nolan: Sandy will take its place in history, but we'll have to wait until it's over to know where

Editor's note: David Nolan is associate professor of meteorology and physical oceanography at the Rosenstiel School of Marine and Atmospheric Science, University of Miami.

(CNN) -- As far as hurricanes go, Sandy is not particularly intense. With peak winds at 90 mph Monday at 5 p.m., it is still classified as a Category One, with only a small chance of briefly achieving the low end of Category Two before making landfall somewhere in New Jersey on Monday evening.

And yet, state and local governments have gone into full alert mode, with schools closed, cities shut down, and evacuations ordered across the Eastern Seaboard. Justifying the alarm are enormous waves arriving onshore, raising the mean water level by a few feet even here in Miami, where the winds are blowing directly offshore.

Sandy could bring 'catastrophe,' affect 60 million

Sandy represents the confluence of a modestly strong hurricane coming up from the Caribbean and a fairly strong but not unusual continental weather system -- what meteorologists call a "trough" or "dip" in the jet stream -- that has been traversing the country over the last few days.

David Nolan
David Nolan

In the vast majority of cases, these weather systems weaken hurricanes while at the same time pushing them quickly out to sea. Such weather systems also generate their own cyclones, not as intense as hurricanes, but larger and slower moving.

Opinion: As Sandy descends, tips from Katrina survivors

Become a fan of CNNOpinion
Stay up to date on the latest opinion, analysis and conversations through social media. Join us at Facebook/CNNOpinion and follow us @CNNOpinion on Twitter. We welcome your ideas and comments.



When these extra-tropical cyclones form over the ocean and move along the coast, we call them nor'easters (for the strong northeasterly winds they generate). Sometimes, tropical and extra-tropical systems merge, and the hurricane turns into a large ocean cyclone. But again, almost all of these storms move quickly out to sea.

There are two elements that make Sandy very unusual, possibly even "super."

First is its pathway. Rather than racing out to sea like most coastal storms, Sandy has already turned hard to the left and it will make landfall at nearly a right angle to the U.S. coastline. This extremely unusual track (from right to left) means that almost every piece of coastline from New Jersey to Cape Cod will receive onshore winds at some point during the event.

ISS flies over Hurricane Sandy
Watch the evolution of the superstorm
Raw video: Long Island flooding

Second, the core of Sandy -- the part that will look and feel like a hurricane -- has remained intact, even as cooler and drier air from the United States wraps around it. Thus, Sandy has each of the worst features of both kinds of storm: a small core of hurricane-force winds around its center, and a broad expanse of gale-force winds extending hundreds of miles outward that will batter the shorelines for several days.

Why did this happen?

It was simply a matter of positioning.

Sandy arrived east of Florida at exactly the right time and place to get the maximum benefits from its interaction with the dip in the jet stream. As a result, Sandy became large enough to influence that system as well, and the two will wrap around each other into a single, deep cyclone, 800 miles across, extending from the ground to 40,000 feet in the sky. This will add to the duration of the event as the circulation takes several days to wind down over Pennsylvania and New York.

Opinion: Climate change raises stakes for coast

As for whether Sandy is a "Superstorm," perhaps we should refrain from such a designation until after the event.

There was already a "Superstorm" in March 1993 -- a nor'easter that dumped snow from New Orleans to Canada. There was the Halloween Storm of 1991 -- later known as the Perfect Storm -- which, like Sandy, also grew from the confluence of a large extra-tropical cyclone and a hurricane (which, unlike Sandy, was destroyed in the process). And there was the Blizzard of '78, the Eastcoaster of 1996, and others.

Sandy will take its place in history, but we will not know what that place is until many days have passed.

Follow us on Twitter @CNNOpinion

Join us on Facebook/CNNOpinion

The opinions expressed in this commentary are solely those of David Nolan.

ADVERTISEMENT
Part of complete coverage on
October 28, 2014 -- Updated 1237 GMT (2037 HKT)
Errol Louis says forced to choose between narrow political advantage and the public good, the governors showed they are willing to take the easy way out over Ebola.
October 27, 2014 -- Updated 1803 GMT (0203 HKT)
Eric Liu says with our family and friends and neighbors, each one of us must decide what kind of civilization we expect in the United States. It's our responsibility to set tone and standards, with our laws and norms
October 27, 2014 -- Updated 1145 GMT (1945 HKT)
Sally Kohn says the UNC report highlights how some colleges exploit student athletes while offering little in return
October 26, 2014 -- Updated 1904 GMT (0304 HKT)
Terrorists don't represent Islam, but Muslims must step up efforts to counter some of the bigotry within the world of Islam, says Fareed Zakaria
October 24, 2014 -- Updated 1302 GMT (2102 HKT)
Scott Yates says extending Daylight Saving Time could save energy, reduce heart attacks and get you more sleep
October 27, 2014 -- Updated 0032 GMT (0832 HKT)
Reza Aslan says the interplay between beliefs and actions is a lot more complicated than critics of Islam portray
October 27, 2014 -- Updated 1119 GMT (1919 HKT)
Julian Zelizer says control of the Senate will be decided by a few close contests
October 24, 2014 -- Updated 1212 GMT (2012 HKT)
The response of some U.S. institutions that should know better to Ebola has been anything but inspiring, writes Idris Ayodeji Bello.
October 22, 2014 -- Updated 2101 GMT (0501 HKT)
Paul Callan says the grand jury is the right process to use to decide if charges should be brought against the police officer
October 23, 2014 -- Updated 1619 GMT (0019 HKT)
Theresa Brown says the Ebola crisis brought nurses into the national conversation on health care. They need to stay there.
October 21, 2014 -- Updated 2235 GMT (0635 HKT)
Patrick Hornbeck says don't buy the hype: The arguments the Vatican used in its interim report would have virtually guaranteed that same-sex couples remained second class citizens
October 24, 2014 -- Updated 1630 GMT (0030 HKT)
The Swedes will find sitting on the fence to be increasingly uncomfortable with Putin as next door neighbor, writes Gary Schmitt
October 24, 2014 -- Updated 1632 GMT (0032 HKT)
The Ottawa shooting pre-empted Malala's appearances in Canada, but her message to young people needs to be spread, writes Frida Ghitis
October 26, 2014 -- Updated 0148 GMT (0948 HKT)
Paul Begala says Iowa's U.S. Senate candidate, Joni Ernst, told NRA she has right to use gun to defend herself--even from the government. But shooting at officials is not what the Founders had in mind
October 23, 2014 -- Updated 2208 GMT (0608 HKT)
John Sutter: Why are we so surprised the head of a major international corporation learned another language?
October 23, 2014 -- Updated 2154 GMT (0554 HKT)
Jason Johnson says Ferguson isn't a downtrodden community rising up against the white oppressor, but it is looking for justice
October 24, 2014 -- Updated 1621 GMT (0021 HKT)
Sally Kohn says a video of little girls dressed as princesses using the F-word very loudly to condemn sexism is provocative. But is it exploitative?
October 21, 2014 -- Updated 2006 GMT (0406 HKT)
Timothy Stanley says Lewinsky is shamelessly playing the victim in her affair with Bill Clinton, humiliating Hillary Clinton again and aiding her critics
October 23, 2014 -- Updated 1414 GMT (2214 HKT)
Imagine being rescued from modern slavery, only to be charged with a crime, writes John Sutter
October 21, 2014 -- Updated 1600 GMT (0000 HKT)
Tidal flooding used to be a relatively rare occurrence along the East Coast. Not anymore, write Melanie Fitzpatrick and Erika Spanger-Siegfried.
October 21, 2014 -- Updated 1135 GMT (1935 HKT)
Carol Costello says activists, writers, politicians have begun discussing their abortions. But will that new approach make a difference on an old battleground?
October 21, 2014 -- Updated 1312 GMT (2112 HKT)
Sigrid Fry-Revere says the National Organ Transplant Act has caused more Americans to die waiting for an organ than died in both World Wars, Korea, Vietnam, Afghanistan and Iraq
ADVERTISEMENT