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Superstorm Sandy: One Year Later - Fire Island Breach
By Paul F on Dec 10, 2013 at 9:13 PM
Superstorm Sandy: One Year Later - Fire Island Breach Photo Journal Series

On YouTube: Forum to be held on Fire Island breach


As seen in the video clip below from News 12 Long Island on December 16, 2013, New York Sea Grant (NYSG)-funded Stony Brook University (SBU) School of Marine and Atmospheric Sciences (SoMAS) researchers Charlie Flagg discusses findings from a new report that details, in December, the size of the inlet has stabilized at around 400 square meters. He says it has remained relatively constant for nine months but may have the potential to get bigger.



In addition to talking with News 12 Long Island, Flagg also spoke about the Fire Island Breach with National Geographic in October 2013. That video clip and transcript are featured in NYSG's news item, "Superstorm Sandy: One Year Later - Long Island Breach." Additionally, Flagg also discussed concerns over the breach with, among other media outlets, Newsday (pdf), The Atlantic (pdf) and The New York Times (pdf), as well as Long Island Business News and Verizon Fios 1 News.


Photo Journal Series: Post-Sandy Eastern Fire Island Breach
With observations by Charlie Flagg; Compiled by Paul C. Focazio

Flagg and fellow NYSG-funded SBU SoMAS investigator Roger Flood's offer insights along with their aerial photograph series that documents the evolution of the breach at Old Inlet from shortly after its inception during Superstorm Sandy on October 29, 2012, to the latest photos taken June 16, 2013. Monitoring of the breach is important, as its evolution will affect the tidal dynamics and the ecosystem of the Long Island's eastern Great South Bay.

For orientation, the first photo taken in April 2005 (pictured below) shows the configuration of the Old Inlet area prior to the breach. In the right-center of the picture, the Old Inlet dock and board walk across the island are visible as is a small embayment that had historically been used to tie up a ferry to bring people to the old beach clubs that were in that area. The inlet formed in area of the embayment and took out the entire boardwalk and part of the dock.


Aerial photo of the Old Inlet area taken by C. Flagg in April 2005.


November 3, 2012
The two photos below were taken on November 3, 2012 near 12:30 GMT, five days after the breach was formed. These are close up shots from the south and southwest of the new inlet in which you can see the breach, the Old Inlet dock that is no longer attached to the island, Pelican Island in the background, and several new sand islands to the north and west. All the photos were taken during flood tide. The new channel swept in from the east and hugs the east side of the breach before most of the flow turns west, south of the new sand islands.


Aerial photo taken by C. Flagg and R. Giannotti on Nov. 3, 2012, from the south of the breach.


Aerial photo taken by C. Flagg and R. Giannotti on Nov. 3, 2012, from the southwest of the breach.

The last in this series of November 3, 2012 photos (pictured below) was taken from nearly directly overhead and clearly shows the relationship between the breach channel and the familiar landmark of the dock.


Aerial photo taken by C. Flagg and R. Giannotti on November 3, 2012, from the west of the breach.


November 11, 2012
A series of aerial photos were taken a week later on November 11, 2012 around 1400 GMT, after a nor’easter passed through the area on November 7 and 8. There were substantial changes to both the main channel through Fire Island and the sand islands in the bay. The initial cut through the island had been fairly straight with the deepest part along the eastern edge. As a result of natural adjustment but probably mostly as a result of the nor’easter, the channel now has a decided offset to the west between the ocean and bay ends of the channel. The offset appears confined to the bay end of the channel while the ocean end does not seem to have moved. Also there is less evidence of a single deep channel.

The most visible changes to the breach occurred in the sand islands that had been formed by dune sands carried into the bay. Right after Sandy, the sand islands were north of Fire Island and west of the inlet with channels between the sand islands, Fire Island and Pelican Island. After the nor-easter the connection with the bay, which had been to the west just north of Fire Island, had completely switched directions and now makes a connection to the old Old Inlet channel to the east. passing under and through the dock as shown in the last photo below. As part of this change was the build-up of what appears to be a fairly high sand island that all but connects Fire Island to Pelican Island with a small channel that passes under the Pelican Island dock. This change in flow pattern now connects the inlet to the rest of Great South Bay through a deeper channel with greater conveyance and that may extend the natural lifetime of the inlet.


Aerial photo taken by C. Flagg and R. Giannotti on November 11, 2013.


November 18, 2012
A follow-up set of photos were taken on Sunday November 18th between 1700 and 1800 GMT. The November 18th photos show that the original channel to the west, just north of Fire Island, had been re-established although much of the sand bar to Pelican Island remained. The western edge of the inlet near the ocean has eroded to the point that the offset on November 11th had disappeared and the ebb-tidal delta clearly exhibits east and west channels connecting the inlet to the ocean.


Aerial photo taken by R. Weissmann and R. Giannotti on November 18, 2013.


December 20, 2012
The next set of photos were taken a month later on December 20, 2012 between 1620 and 1700 GMT. Meteorologically, not much had happened between the November 18 and December 20 photos, so there was a more gradual evolution of the inlet as shown by a comparison between Figures 4 and 5. The most notable change was the disappearance of the sand island south of Pelican Island, and the channel to the west, which had been along the north shore of Fire Island, moved north closer to Pelican Island. There also were changes to the inlet. The eastern side of the inlet had migrated somewhat to the west. A bit of a bar had formed off the east side shown by the breaking waves. And the low sand beach along the western side had eroded away. The ebb shoal delta again visible in the area of breaking waves and the east and west channels are also evident.


Aerial photo taken by M. Ferrigno and R. Giannotti on December 20, 2012.


December 22, 2012 - January 6, 2013
In late December, there were a couple of storms that have again altered the configuration of the inlet at both the ocean and bay ends. On December 22 and 23. there was a sustained period of high westerly winds, which caused a significant water level rise in Bellport Bay. This event was followed a few days later by the passage of a nor’easter on December 27, which caused a second period of high water level. The combination of these storms have resulted in quite noticeable changes in the configuration of the inlet and the back bay channels, as shown by photos taken on January 6, 2013 around 2000 GMT.


Aerial photo taken by C. Flagg on January 6, 2013.

Along the ocean beach to the east of the inlet, an offshore bar formed that moved onshore creating a series of ridges and runnels that eventually connected to the ebb shoal. The ridge/runnel system extended all along the beach to the east, and so was not particularly associated with the inlet morphological dynamics. However, as the offshore bar moved onto the beach, it cut off the east channel and forced all the tidal flow to use the west channel, which caused it to enlarge and move into the center of the inlet. As part of that process, it appears that the ebb shoal delta has eroded away. At the same time, there was significant deposition along the eastern edge of the inlet especially at the northern end. Along the western edge of the inlet, there has been considerable erosion with the shoreline moving up to the scrub line.

In the back bay area, a substantial sand island has formed causing the formation of two channels to the west, one along the west side of Pelican Island and second one just north of Fire Island.

The clarity of the water made the underwater shoaling to the north of the inlet visible in a couple of the photos taken on January 6th and two of these photos are shown in the two photos below. The sand island and shoaling that extends off to the northwest of the inlet is at least 0.5 km long, while the shoals to the east of Pelican Island extend about 0.6 km from the inlet.


Aerial photo of the inlet from the northwest showing the extended sand island and shoals to the west of the inlet. Photo taken by C. Flagg on Jan. 6, 2013.


Aerial photo of shoals to the northeast of the inlet. Photo taken by C. Flagg on January 6, 2013.


January 27-February 14, 2013
In the three week period between the photo above and below (1/6-1/27), there has been a period of strong, but not storm, winds out of the west, and in the last week the weather has been cold enough to freeze much of eastern Great South Bay. The evolution of the inlet on the bay side was not that extensive, but there were significant changes at the ocean end, as pictured below. The offshore bar that was in the process of moving shoreward on January 6th has completed that process, and the sand associated with the ridge and runnel system along the eastern beach has completely joined the beach. The sand, which was part of the offshore bar that extended into the inlet, has attached itself to the eastern edge of the inlet, while the sand at the northeast corner of the inlet has disappeared. The ridge and runnel system that had been prominent along the eastern beach has now formed along the western beach and extended into the inlet forming a new ebb tidal delta, while the main channel appears to have shifted slightly to the east as a result. And there has been some additional erosion of the dune to the west.

The water was extremely clear during this latest over flight, which permits a good view of the channels in the back bay area. These channels show up quite prominently in the photo below as does the extensive area of sand deposited in the Bay as a result of the inlet formation and overwashes to the east. It now appears that there is one major channel to the west close along Fire Island and two possibly shallower channels to the northeast past Pelican Island. There had been snow during the previous week so anything that shows up white is clearly above the high tide line and that includes a number of portions of the new sand islands.


Aerial photo taken by C. Flagg and D. Richards on January 27, 2013.

For the flight on January 27th, a video camera was fixed to the plane so that it looked straight down providing photos with minimal spatial distortion and from which one can make direct measurements. A mosaic of video snapshots (courtesy of Mark Lang) taken of the inlet from a height of 2000 feet is shown in the photo below. To get a scale, one can use the remnants of the Old Inlet dock that measures about 52 meters from the cross of the “T” on the northwest end to the last piece of the dock to the southeast. If we use that as a scale, the narrowest part of the inlet is about 85 meters across while the deepest part of the channel, marked by the darkest colors, appears to be about 25 meters across. The narrowest part of the channel to the west is also about 25 meters wide while the channels to the northeast, although not that well defined, vary from 10 to 20 meters wide. The flood delta shows several lobes and channels, and it is clear that some sand deposits are now above water, since there is white snow evident in many places that in the past were under water. At the ocean end of the inlet, the light colored sand shows quite a bit of shoaling to the west and even a small bar forming along the eastern edge of the main channel.

It does not appear that there were significant alterations to the inlet's inner portion from the January 31 wind event. Even the offshore bar and runnel structure and offshore bar had changed but little. It was a completely different story as a result of the February 8-9 blizzard during which winds were initially out of the east before rotating to the north and northwest. Water levels in the bay again reached fairly high values of around 0.75 m above the long-term mean before retreating. This time it appears that the setup against the island caused by the east wind was responsible for the increased water level, overcoming the local downwind setdown in the bay.


Photo mosaics of the inlet taken on January 27, 2013 (left) and February 2, 2013 (right). For scale, the remains of the Old Inlet dock is about 50 m long. Photos By C. Flagg and D. Richards, Compiled into mosaic by Mark Lang.

The photo below was taken on February 14, 2013, just a few days after a winter blizzard. Over a period of three weeks in early February, the eastern tip of the inlet’s western border showed about a 50 meter retreat to the west (#1 on photo) and a large sandbar was building up on the eastern shore (#2). At the same time, the main channels into Bellport Bay passed close along Fire Island to west and south of the Old Inlet dock to the east (#3), with some flow passing on either side of Pelican Island. Although not shown in the photo below, the channels all led to fan-shaped regions of shallow water often less than a foot deep at low tide. A bathymetric survey of the breach area on February 22, a week after the photo, indicated that there was a narrow channel about 7 m deep just off the tip of the western shore where the currents were the highest. At the northern and southern ends of the inlet, the water depths were between 2 and 3 m as the currents spread out and slowed down.


Photo mosaic from February 14 taken about an hour before sunset near low tide. Photos By C. Flagg and D. Richards, Compiled into mosaic by Mark Lang.


March 29-June 21, 2013
The photo mosaic below, from March 29, is quite similar to another one taken of March 10, although the shoaling in the channel to the west just north of Fire Island has increased. Also by the end of March the sand bar that had moved into the inlet along the eastern side had increased in size and consolidated. Evident in the March 29 and subsequent photos is a runnel area between the eastern sand shoal and Fire Island to the east. This runnel area has waxed and waned over the past three months indicating that while the eastern sand shoal remains low enough to be flooded at times, it has not been accessible to overwash for enough sand to be deposited to fill the depression.

Photo mosaics from March 29 and April 17, 2013. Photos By C. Flagg and D. Richards, Compiled into mosaic by Mark Lang.


The major alterations to the inlet since the end of March involve the development of a sand spit off the northwest corner of the inlet. On March 29th (as pictured above) there was just a small indication of a sandy area at the tip of the island. The spit grew noticeably by April 17th (as pictured above) and the shoal at the entrance to the westward channel had grown as well essentially cutting off the channel along the north side of the island.

By a month later on May 12th (as pictured below) the spit had grown to an area of about 200 meters by 100 meters and reduced the western channel even further. At the end of May, the enlarged sand spit remained and one can see that flow to the west had formed a new channel north of the spit.


Photo mosaics from May 12 and May 31, 2013. Photos By C. Flagg and D. Richards, Compiled into mosaic by Mark Lang.

The evolution of the spit continued into June (as pictured below) when a small nor’easter on June 8th caused the erosion of the northern end of the spit evident in the June 16 photo. Some erosion of the spit had taken place on the west side, but most of it occurred in the inlet area. The sand however was not washed out of the inlet but rather built up an extensive shoal along the spit to the east. When we were out in the inlet for another bathymetric survey on June 21st during an ebb tide, the water was boiling over this shoal and it was quite shallow. While the spit on the west was eroded as a result of the June storm, an extensive shoal area formed along the east side of the inlet extending from the northeastern corner of the inlet southward highlighted by the breaking waves in that area in the photo below.


Photo Mosaic from June 16, 2013. Photos By C. Flagg and D. Richards, Compiled into mosaic by Mark Lang.

The changes in the back bay sand island, shoals and channels have not been as dramatic as the changes in and along the inlet, but the evolution of that area continues. In particular, the channels and shoals off to the northeast keep changing. Since the storm at the end of February when the gun club house on Pelican Island moved about 100 meters to the north, the area under the house’s previous location has been part of a major channel to the north and east. The channel on the west side of Pelican Island heading off to the north has also increased in size. Early on in the development of the inlet, the main channel to the east skirted along the north shore of Fire Island. That channel has varied in size and location. Initially it was south of the Old Inlet dock about which a sand shoal had formed. But later that shoal shifted and spread out to the east, and there is now considerable flow through the old dock. Much of the flow to the north and east is now funneled into an area along the Fire Island shore near a little round island known as Hospital Island. From there the flow splits, some of it spreads out and flows off toward the Smith Point Channel and some flows to the northwest, west of John Boyle Island.

Also, by the end of May the ocean beach to the west of the inlet had built up considerably. This sand accretion extended along the west side of the inlet and has remained.

On June 15th the remains of the displaced gun club house were removed. When it moved off the island on February 28th it sank in several feet of water and caused the flow in that area to slow down and deposit sand around the house. So a shoal and sand island formed around the house which is visible in all the photos since then. However the photo taken on June 16th (pictured above) - the day after the house was removed - already shows that the sand shoal around the house was beginning to erode away.


December 19, 2013 - January 21, 2014

Photo Mosaic from December 19, 2013 and January 21, 2014. Photos By C. Flagg during overflight surveys of the Inlet, Compiled into mosaic by Mark Lang.

While a large and long west bank had been developing within Great South Bay’s New Inlet during the fall months, strong storms during January 2014 blew out this accumulation of sand, effectively widening the Inlet and possibly enhancing circulation.
Tags: #hurricane
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