It's the most infamous left turn in weather history.
One year ago, as Hurricane Sandy roared up the East Coast, it was about to make its unprecedented turn to the west, heading for its ferocious and tragic landfall in New Jersey as a "Superstorm" on Oct. 29, 2012.
How unprecedented? "We looked into the tracks of past hurricanes, and there's not a single track like Sandy," according to Peter Hoeppe, head of geo risks research with global insurance firm Munich Re.
In fact, in more than 100 years of weather records, "this is the only one that turned back to the west," noted National Weather Service director Louis Uccellini.
Sandy killed at least 117 people and caused $50 billion in damage in the U.S., making it the second-costliest weather disaster in American history behind only Hurricane Katrina, according to the National Oceanic and Atmospheric Administration.
The computer models meteorologists use to forecast weather eventually came together to forecast Sandy's weird path, though it took the main U.S. weather model a while to come on board: "Sandy taught us that our weather models are pretty good," said J. Marshall Shepherd, president of the American Meteorological Society and professor at the University of Georgia.
A week before Sandy hit land, Shepherd said, weather models picked up on a very complex interplay among the hurricane, a developing storm over the U.S., and an area of high pressure over the North Atlantic. It was this area of high pressure that prevented, or "blocked" Sandy from moving out to sea, instead driving it back toward the U.S. "The models nailed the very unusual 'hard left," Shepherd said.
This forecast allowed the weather service to warn emergency managers about the storm threat well ahead of time: "We certainly got people to act in the right way in terms of evacuations, closing subways, getting trains repositioned, and so on," said Uccellini. "We're feeling very good about that. Through our actions, countless lives were saved in New Jersey, New York, Long Island and New England."
WEATHER MODEL NEEDS IMPROVEMENT
However, there is admittedly room for improvement, especially in the American weather models, as it was the main European weather model that did a better job than the top U.S. model at first picking up Sandy's unusual forecast track.
"The discussion about the European vs. the American model performance probably helped to bring into focus that our weather assets are national assets, like aspects of homeland security or defense," Shepherd said. "Sandy helped to raise this issue and now the weather service has received support to help in this matter."
(Shepherd is referring to the $97 million that the weather service received to upgrade its forecasts, computer models and research budgets from the U.S. Congress' "Sandy Supplemental bill" earlier this year.)
Improved storm surge forecasts are also on the way in the next couple of years, Uccellini says, a needed improvement due to the tremendous damage that storm surge causes: It was Sandy's monstrous storm surge that wreaked the most havoc in New Jersey.
Also, Sandy forced the weather service to change the way that it forecasts hurricanes. Since Sandy was not forecast to be a hurricane at landfall, the weather service did not issue hurricane warnings as the storm approached, which led to some public confusion; at one point, New York City Mayor Michael Bloomberg downplayed the storm's ferocity, since it was not predicted to be a hurricane as it neared the coast.
But from now on, according to Uccellini, the National Hurricane Center will continue to issue advisories on storms even after they've gone "post-tropical" as Sandy did. This will allow for greater flexibility into how the hurricane center communicates about storms, he said.
A CLIMATE CHANGE CONNECTION?
Could more Sandys be in our future due to climate change? While no one claims that Sandy was due to global warming, Hoeppe said that some factors, such as warmer ocean waters, sea-level rise, and changing atmospheric patterns could contribute to stronger storms.
Overall, in the past 100 years, sea level in the New York region has risen about a foot, two-thirds of it caused by man-made climate change, according to Princeton University professor Michael Oppenheimer.
"Remember, Sandy was not a major hurricane - in fact it was barely a hurricane - but it was devastating to this populated coastal region," Shepherd said. "With increasing sea level, the public should be aware that it will not take Katrina- or Andrew-type storms to produce damaging surge and inundation."
Global average sea level could rise by more than 2 feet by the end of the century, according to the most recent report from the Intergovernmental Panel on Climate Change.
"I think, hopefully, Sandy has gotten academia, the private sector, and the federal government to move beyond 'lip service' on social science, communications and related research," he added. "I think we saw with Sandy and the tornadoes this year that we can have a great forecast, yet communications, perceptions and language barriers can still create loss of life."
And though this hurricane season has been very quiet, it's no time to get complacent: "It's just a matter of time before another big storm," said Peter Raab, head of property underwriting at Munich Re.
By Doyle Rice, USA Today; contributing: Associated Press