Dr Jeff Masters on this year’s Wild Weather

One of the unexpected pleasures I had last week at the American Geophysical Union conference was meeting Dr. Jeff Masters of WeatherUnderground, one of the web’s premier weather and climate resources.

Jeff has a new post reviewing this past year’s wild weather.  When we envision hurricanes, we don’t usually think of Binghampton, NY…..

Wunderground.com:

With one of the wildest weather years in U.S. history drawing to a close, it’s time to look back at some of this year’s unprecedented onslaught of billion-dollar weather disasters–and the lessons we should have learned.

One of these disasters was the approximately $1 billion in damage due to flooding from Tropical Storm Lee, which brought torrential rains along a swath from Louisiana to New York in early September. Among the hardest hit cities was Binghamton, New York (population 47,000), where record rains due to the remnants of Tropical Storm Lee on September 8 brought a 1-in-200 to 1-in-500 year flood to the city’s Susquehanna River. A flood 8.5 inches higher than the city’s flood walls spilled over into the city that day, damaging or destroying over 7,300 buildings in Greater Binghamton, and causing tens of millions of dollars in damage.

Damage to Binghamton’s sewage treatment plant and city infrastructure alone are estimated at $26 million. Damage to one elementary school is estimated at $11 – 19 million. There is as yet no damage estimate for private property losses, but they will undoubtedly be in the tens of millions. Damage to private property in the county immediately downstream from Binghamton, Tioga County, is estimated at over $100 million.

I argue that there is strong evidence that the extra moisture that global warming has added to the atmosphere over the past 40 years could have been “the straw that broke the camel’s back” which allowed Binghamton’s flood walls to be overtopped, causing tens of millions in damages. Had this event occurred 40 years ago, before global warming added an extra 4% moisture to the atmosphere, the Susquehanna flood would have likely stayed within the city’s flood walls.

More Pics below…

This year’s flood is the second 1-in-200 to 1-in-500 year flood in the past five years to hit Binghamton. On June 26 – 29, 2006, tropical moisture streaming northwards over a front stalled out over New York state brought over thirteen inches of rain to portions of southern New York.

The Susquehanna River swelled to record levels, triggering devastating flooding that cost at least $227 million. In Binghamton, the Susquehanna River crested eleven feet over flood stage, the greatest flood since records began in 1846. The flood walls protecting Binghamton were overtopped by a few inches, allowing water to pour into the city and cause tens of millions of dollars in damage. This flood is another example of a case where global warming may have been “the straw that broke the camel’s back”, allowing the flood walls to be overtopped by a few inches.

While it is not impossible that the 2006 flood and the 2011 flood could have occurred naturally so close together in time, such a rare double flood has been made more likely by the extra moisture added to the atmosphere due to global warming.

Irene set the stage for what was to become the greatest flood in recorded history on the Susquehanna River. On September 5, a front stalled out over Pennsylvania and New York. Tropical moisture streaming northwards in advance of Tropical Storm Lee was lifted up over the front, and heavy downpours resulted.

The rains continued for four days, and were amplified by the arrival of Tropical Storm Lee’s remnants on September 7, plus a stream of moisture emanating from far-away Hurricane Katia, 1,000 miles to the south-southeast. Binghamton, New York received 8.70″ of rain in 24 hours September 7 – 8, the greatest 24-hour rainfall in city history. This was nearly double the city’s previous all-time record (4.68″ on Sep 30 – Oct. 1, 2010.)

The record rains falling on soils still saturated from Hurricane Irene’s rains ran off rapidly into the Susquehanna River, which rose an astonishing twenty feet in just 24 hours. By noon on September 8, the rampaging Susquehanna River crested in Binghamton at 25.71′, the highest level since records began in 1846. The river would have risen higher had the city’s flood walls been higher, but since the water was overtopping the flood walls and spreading out over the city, the river was limited to how high it could rise.

By month’s end, precipitation in Binghamton for September 2011 totaled 16.58″, more than thirteen inches above normal, making it Binghamton’s wettest month since records began in 1890.

We can thus see how the record Susquehanna River flood of September 8, 2011 was due to a convergence of rare events, which included moisture from three tropical cyclones:

1) The unusually heavy rains during the first four weeks of August, before the arrival of Hurricane Irene.

2) Hurricane Irene’s 3 – 5 inches of rain.

3) The extreme rains from Tropical Storm Lee’s remnants.

4) The enhanced rainfall on September 7 – 8 due to a moisture plume from Hurricane Katia.

worth reading the rest at Wunderground, here..