“Thanks” to Hurricane Sandy, students all around New York City have been rejoicing over their nine-day weekend. To some of us, Sandy is the source of a school break. To others, she’s the source of damage and lost loved ones. But where did all of this begin? What’s really behind the nature of this beast?
Now we’ll take a look at how it all started. Hurricanes form from deep cumulonimbus clouds that take in warm water, creating columns of moist air. As these clouds form, air flows from the high-pressure atmosphere into the low-pressure column. Once the air begins moving into a region, the earth’s rotation causes the air to rotate as well. Evidently, Hurricane Sandy followed this textbook pattern. Her final product may even be one for the books of the future.
Many people would assume that Hurricane Sandy, like many other hurricanes, originated somewhere in the Caribbean. But a meteorologist would probably reference Africa in response to the question of Sandy’s roots.
Surprisingly, most slow, progressive, long-lived hurricanes like Sandy have humble origins, first born as tropical waves over the Sahara Desert and then moving into bordering coastal waters. These waves are composed of an organized array of thunderstorms that attain energy from the ocean somewhere between 15 and 30 degrees north of the equator. The waters here usually have temperatures higher than 80 degrees, providing ample amounts of moisture-rich air and humidity to fuel potential hurricanes.
The ostensibly harmless wave that would evolve into the ferocious Frankenstorm traveled westward towards the Caribbean. When Sandy began to exhibit signs of characteristic counterclockwise rotation on Monday, October 22, meteorologists were alerted with the possibility of eventual hurricane development. At 8 p.m. the same day, this brewing storm was upgraded to a topical storm. That Wednesday morning, Sandy became an official category 1 hurricane.
After this post-tropical cyclone departed from Jamaica on Thursday, a blocking high pressure system began to form over Bermuda, spanning across territory near Newfoundland and the Canadian Maritimes. This system diverted the air around it into two different paths. After a few hours, it was perfectly clear as to which path Sandy had taken: she chose the western path, paralleling the Gulf Stream in the direction of the eastern seaboard…en route to hit the United States.
To better understand this concept, try to imagine a container of oil and water. “If you combine oil and water in a container, the oil will sit on top of the water. If you tilted the combination, the surface would slope. The return from that slope to a level plane represents the conversion from potential energy to kinetic energy,” explains the investigator and research professor for the University of Virginia’s department of environmental science, Michael Garstang.
Once Sandy arrived, scientists began to realize that this type of storm is an unprecedented one, an animal that has yet to be seen. Sandy was ultimately worsened by the collision of three large air masses: an ordinary hurricane off the coast of Florida, jet stream coming in from the Arctic, and another storm coming in from the West. These forces joined to form the Frankenstorm that devastated millions and left major cities in pieces.
Much of Sandy’s damage was a result of storm surge, making it a great threat to life and property for those living on the coast. So how do winds create a storm surge? In a tropical cyclone like Sandy, air pressure is highest at the edges and lowest at the center. Air gusts at speeds of over 74 miles per hour, filling that low-pressure center. The low pressure itself also helps to raise the level of the sea and ultimately elevate the surge.
Sandy’s crippling storm surge was a result of this post-tropical cyclone’s track. As Jamie Rhome, the storm surge team leader at the National Hurricane Center, said:
“Storm surge is like real estate: location, location, location.”
In this case, the New York Harbor’s surrounding coastline acted as a funnel, channeling more and more incoming water into an increasingly narrow region. When a large volume of water is confined like that, “it has no choice but to spill out and flood the surrounding land,” as Rhome stated.
New York is especially vulnerable to storm surge because of its 500 miles of coastline, including small bays, inlets, and other potential funnels that are able to channel rising water far inland.
Some are suggesting that this monster was man-made, not unlike the one in Mary Shelley’s novel. The Intergovernmental Panel on Climate Change has reported that over the hundred-year period starting in 1906, the average global surface temperature increased by over 0.74 degrees Celsius, and oceans have taken over 80% of the heat that is added to the climate system. Much of this is likely due to greenhouse gas emissions, pollution, and the like. Since hurricanes are fueled by warm waters, as previously mentioned, this seems like an obvious fit, for according to the IPCC, “There is observational evidence of an increase in intense tropical cyclone activity in the North Atlantic since about 1970.”
Many people are saying that this superstorm is just what was needed to silence climate science deniers. As New York Governor Andrew Cuomo said, “For us to say this is a once-in-a-generation, that it’s not going to happen again, as elected officials that would be short-sighted. This city, this region, is very susceptible to coastal flooding. Part of learning from this is learning that climate change is a reality.” After all, Sandy has been named the 18th storm in the 2012 Atlantic hurricane season thus far.
As you may remember from watching clips from An Inconvenient Truth in Ms. Wolf’s biology class, Al Gore demonstrated the possibility of superstorms like Sandy and how they may one day flood and destroy major U.S. cities, like New York. Well, that hypothetical ‘one day’ became a real one with Sandy.
Scientists have been trying to deliver this message of climate change for a while now; however, it’s unclear as to whether this storm will galvanize political opinion and lead to concrete action about the issue. Many view this disaster as evidence that climate change is a reality, while others argue that these storms would have occurred in any case.
Human-driven global warming, as mentioned earlier, is creating an environment capable of amplifying the energy of superstorms. Sea levels are also more than seven inches higher than they were at the beginning of the 20th century, allowing storms to do even more damage. Most scientists link this fact directly to climate change.
As Kevin Trenberth, head of the Climate Analysis Section at the NCAR, explained, “Most of what’s going on, if you turn it around, you’d say 90 to 95 percent is due to natural variability. There’s a large element of chance on aspects of these things. But when you’re already stretching the limits and you’re at very high levels of rainfall, if you add a little bit extra on – especially 10 percent extra on – that can really break things.” And that does seem to be the type of routine we’re seeing.
“The human component is only going to grow over time,” Trenberth said.
Gary Yohe, a professor of economics and environmental studies at Wesleyan University, thinks the story is only just getting started: “What we have been experiencing recently is only the harbinger of a future that will be punctuated by more severe weather extremes and increasing damage, all driven by past and future emissions of heat-trapping gases.”
The atmosphere is changing, and our climate is changing in direct proportion with it. We have to begin accepting the fact that we are seeing climate change before our eyes. And as Bill MicKibben, the environmentalist and founder of the climate action group 350.org, puts it, “[The atmosphere] is not the one we were given, it’s increasingly one we’ve made.” Hurricane Sandy shows just that.
Watch this time-lapse animation that shows Hurricane Sandy from the vantage point of geostationary orbit, 35,800 km (22,300 miles) above the Earth. The animation shows Sandy on October 28, 2012, from 7:15 am to 6:26 pm.