Monthly Archives: October 2014

Super-Storm Sandy: Two Years Later

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Two years ago today, Super-storm Sandy slammed the New York City tri-state area.  Despite being downgraded from hurricane to post-tropical status just prior to landfall, Sandy was the second costliest natural disaster in U.S. history, following Hurricane Katrina in 2005. The question is, can it happen again?

Coming ashore with tropical storm-force winds at high tide during a full moon, Sandy was an unprecedented storm. It formed late in the season, grew as it moved north, and instead of turning out to sea like most tropical systems, it made that now famous left hook toward the coast. Statistically, Sandy’s unusual trajectory was a 1-in-700-year event, according to a recent study by researchers at NASA and Columbia University. That said, as sea levels continue to rise, future storm surges will have a higher starting point and be able to reach further inland. So, a lesser storm could produce similar, if not worse, flooding in the future. A different study in the journal, Nature Climate Change, predicts that a current “500 year” storm surge event in NYC could happen every 50 to 240 years by the end of the century.

Sandy caused a record 13.88-foot storm surge at the Battery in lower Manhattan.  It flooded many low-lying areas, including parts of the NYC subway system.  The massive storm, according to the CDC, directly claimed the lives of 117 people in the U.S – mostly by drowning. Damaging or destroying more than 650,000 homes, Sandy displaced thousands of people and caused approximately $70 billion in property damage in addition to knocking out power to 8.5 million people for multiple days.

In reaction, many government agencies – at all levels – have been re-evaluating their strategies for dealing with future storm surge flood disasters.  The National Hurricane Center changed its policy for issuing warnings on post-tropical storms and has developed an experimental Potential Storm Surge Flooding Map that depicts the risk associated with a storm surge during a tropical cyclone. In NYC, the Office of Emergency Management   re-drew its hurricane evacuation zones to reflect the threat of higher sea levels.

As these types of important improvements are being made, the arduous process of rebuilding homes and installing physical defenses against future storms is still ongoing, especially in  the region’s hardest hit areas.

NYC Sea Level Rising Faster than Global Average

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Sea level is on the rise around the globe. Some areas, such as New York City, however, are seeing the water rise faster than others.

According to the latest IPCC report, the average global sea level has risen about eight inches since 1880.  Locally, in New York Harbor, the water has risen by more than a foot in the past century. The graph below shows the upward sea level trend at the Battery, Manhattan’s southern tip.

In general, sea level rise has two main drivers. They are thermal expansion – a process in which water expands as it warms – and the melting of land based ice, such as glaciers and ice sheets. Both are the result of rising global temperatures. On the local level in NYC, there is also the issue of glacio-isostatic adjustment. This process is not caused by current glacial melt, but rather by the modification of the Earth’s surface as it slowly responds to the removal of the massive weight of ancient glaciers. Overall, it causes some land surfaces to rise and others to sink.  In NYC, the land is slowly sinking.  This combination of factors is expected to intensify future storm surge events in the city.

Sea level in NY Harbor is rising faster than the global average. Credit: NOAA

Sea level is rising in NY Harbor.   Credit: NOAA

Warmest September on Record for Planet Earth

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Temperatures across the globe soared last month. In fact, September 2014 was the warmest September ever recorded for the entire planet.

According to a report released Monday by NOAA’s National Climatic Data Center, Earth’s combined average temperature for the month – over both land and sea surfaces – was 60.3°F.  That is 1.3°F above the 20th century average. September 2014 also marked the 355th consecutive month that our global temperature was above its long-term norm.

This record warm September comes on the heels of the planet’s warmest summer and marks the fourth month this year to break a global temperature record. The other three months were May, June, and August. It is also interesting to note that all four of these monthly heat records occurred when El Niño conditions were not present in the Pacific.

Year to date, 2014 is now tied with 1998 for the warmest first nine months of the year on record. NOAA says, “If 2014 maintains this temperature departure from average for the remainder of the year, it will be the warmest year on record.”

The contiguous United States, by comparison, posted its coolest September in three years. This highlights the fact that climate change is a complex global phenomenon that involves much more than what is happening in our own backyards. Global temperature records date back to 1880.

Credit: NOAA

Credit: NOAA

Hurricane Gonzalo Blasts Bermuda

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Gonzalo, the 7th named storm of the 2014 Atlantic hurricane season, made landfall in Bermuda on Friday night. Despite being downgraded from a category-3 to a category-2 hurricane just prior to coming ashore, the storm still caused extensive damage.

Producing a top wind gust of 140-mph and generating waves over 40 feet high, the storm toppled trees and downed power lines. Approximately 90% of the island chain lost power. Crediting advanced preparations, local officials say no fatalities or serious injuries have been reported.

Gonzalo was the second tropical system to hit Bermuda is less than a week. Tropical Storm Fay slammed the popular vacation spot just last Sunday with strong winds and heavy rain. The last time Bermuda was hit twice in one week was when Tropical Storm Emily and Hurricane Floyd both moved over the archipelago in early September 1981.

Hurricane Gonzalo makes landfall in Bermuda. Credit:

Hurricane Gonzalo makes landfall in Bermuda. Credit: PTZ_TV

Autumn Considered the Second Season for Tornadoes

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Spring is the season most commonly associated with twisters in the United States. Autumn, however, can be just as dangerous and is known as the “second season” for tornadoes.

According to NOAA, approximately 1200 tornadoes touch down in the US every year. While most occur in “Tornado Alley”, in the central part of the country, activity there tends to peak in May. The second season is most active in the mid-south, an area often referred to as “Dixie Alley”.

During the transitional months of autumn, the jet stream frequently dips south bringing cooler air into the region. At the same time, warm, moist air is flowing in from the Gulf of Mexico. When these two different air masses meet, the local weather can get very active. In fact, some of the largest tornado outbreaks of any month have occurred in October and November.

Credit: USTornadoes

Credit: USTornadoes.com

Credit: USTornadoes

Credit: USTornadoes.com

Sea Level Rise Driving Increase in Tidal Flooding

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Flooding caused by high tides is often called “nuisance flooding”.  As sea levels rise, however, tidal floods are expected to become a more serious problem.

According to a report released this week by the Union of Concerned Scientists, coastal communities along this country’s East and Gulf coasts should expect to see a dramatic increase in tidal flooding over the next 30 years. Analyzing data from 52 tide gauges from Maine to Texas, researchers looked at how often communities flood now as compared to the past. They found that some areas have seen a fourfold increase in the annual number of flood days since 1970. Using a mid-range scenario of future sea level rise from the 2014 National Climate Assessment, the scientists forecast that, “more than half of the 52 communities can expect to average more than two dozen tidal floods per year by 2030.” Some areas, especially in the mid-Atlantic, can expect a tripling in the frequency of tidal flood events.

The report also states, “This flooding will define how and where people in affected areas live, work, and otherwise go about their daily lives.” Recognizing the need to adapt, the report offers “sensible steps for building resilient coastal communities.” These include upgrading infrastructure and developing both short and long-term plans to deal with sea level rise.

A tide that causes a minor flood today is a nuisance (white arrow). In the future, higher sea levels will allow high tides to push water deeper into coastal communities, affecting more homes, businesses, and infrastructure. Extensive moderate flooding—now usually associated with storms and high winds—is expected to become more common, simply from high tides. Credit: UCS

Flooding – now usually associated with storms – is expected to become more common, simply from high tides.  Credit: UCS

Microburst Winds Damage Town in Massachusetts

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A strong microburst toppled trees and power-lines in the town of Easthampton, Massachusetts early Wednesday morning. With winds in excess of 100mph, the damage to the area was equivalent to an EF-1 tornado.

According to the National Weather Service in Boston, the powerful storm cut a path of destruction one mile long and a quarter mile wide. No serious injuries have been reported.

A microburst is a powerful, but short-lived, downward moving column of air generated by a thunderstorm. It produces intense straight-line winds – as opposed to the rotating winds of a tornado – that generally impact localized areas less than 2.5 miles wide.

microburst

How a mircoburst works.   Credit: NOAA

Damage from microburst in Easthampton, MA. Credit: MassLive

Damage from microburst in Easthampton, MA.   Credit: MassLive

“Extreme Whether” – A Play about Climate Change

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Science and the performing arts have joined forces to expand the public discourse on climate change.   In Extreme Whether, a play written and directed by Karen Malpede, the issue is viewed through the personal lens of a bitter family fight over land stewardship.

Set during the record warm summers of 2004 and 2012, the “eco-drama” unfolds on a private wilderness estate in the northeastern U.S.  Leading one side of the battle is a famous – and frequently criticized – climate scientist. Heading up the other side is his twin sister, a spokesperson for the energy industry. While all the characters in the play are fictional, some of them are inspired by the work of real scientists.  These include,            Dr. James Hansen, who testified before Congress about the dangers of global warming back in the 1980s; Dr. Jennifer Francis, who researches connections between melting ice in the arctic and wavier jet stream patterns in the mid-latitudes; and Dr. Michael Mann, author of “The Hockey Stick and the Climate Wars.”

Extreme Whether is currently playing at the Theatre for the New City in Manhattan’s East Village. It runs through October 26th.  In conjunction with the show, the theatre is also hosting a “Festival of Conscience” where various climate and environmental experts speak with audience members after the play. For the schedule of speakers, visit: http://theaterthreecollaborative.org

LDEO Open House 2014

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The Lamont-Doherty Earth Observatory – part of Columbia University’s Earth Institute – will be hosting an Open House on Saturday, October 11th. This public event offers tours, lectures, and panel discussions on a range of earth science topics, including climate change.  The program also includes a talk about the long and short term responses to Superstorm Sandy.

For more information, including directions and the day’s schedule, visit the LDEO website.

NYC Monthly Summary: September 2014

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September 2014 was warm and dry in New York City. The month saw temperatures reach into the 90s on two separate occasions and it even produced our hottest day of the year. All together, despite a few cooler than average days in the middle of the month, the city’s mean temperature for September was 69.9°F. That is 1.9°F above average.

In terms of precipitation for September, rain events were few and far between. Only 1.21 inches of rain was measured in Central Park, which is 3.07 inches below normal. That makes September 2014 the city’s driest September in nine years. As a result, the city, along with most of the southeastern section of New York State, is currently listed as “abnormally dry” on the U.S. Drought Monitor.

Graph Credit: The Weather Gamut

Graph Credit: The Weather Gamut

Credit: US Drought Monitor

Credit: US Drought Monitor