Sandy Sets Records and Reshapes Coast

It’s been a long few days covering Sandy but my long days are nothing compared to the people throughout the northeast who have lost homes, businesses, or even loved ones.

Sandy brought a storm surge that was devastating to the Connecticut shoreline. In many respects, however, we dodged a bullet.

Water levels reached benchmarks that haven’t been seen since the 1938 hurricane in some towns. Thankfully, the peak storm surge was reached several hours before high tide.

The storm moved ashore in New Jersey and winds began to diminish prior to high tide’s arrival. In the case of the central and western Sound the peak wind and surge occurred just an hour after low tide and 5 hours prior to high tide.

Here is a look at the Stamford Hurricane Barrier observed water level, predicted astronomical tide, and residual/surge which is the difference between observed water level and what the astronomical tide would be without a storm surge.

Stamford Hurricane Barrier (Courtesy: Army Corps of Engineers). Green – astronomical tide, Blue – observed water level, Pink – surge/residual.

The maximum storm surge at the Stamford Hurricane Barrier was an incredible 11.24 feet! That surge peaked around 7:00 p.m. when the astronomical tide level was quite low. The maximum water level of 11.03 feet was reached at 10 p.m. when the surge had dipped to 8.73 feet. By high tide (around midnight) the surge had dipped to 4.4 feet.

At the Battery in New York City  the peak surge coincided with high tide. The same occurred along a large swath of the Jersey Shore.

The storm surge, however, was still catastrophic on parts of the Connecticut shoreline even though the worst case scenario was narrowly avoided. Many towns, including Milford and Fairfield, experienced coastal flooding worse than Irene and the worst since the great hurricane of 1938. In New London the tide reached a level not seen since hurricane Carol in 1954.

Had the peak winds (which occurred around 6:00 p.m.) and the peak surge (which occurred around 7:00 p.m.) occurred several hours later the destruction in Connecticut would have been unimaginable.

A last minute increase in the storm’s forward speed saved the state from what would have been its greatest natural disaster since the 1955 flood.

If Sandy made landfall in New Jersey closed to midnight entire neighborhoods would have been decimated, inundated by a storm tide 4 or 5 feet higher than what we saw. This would have most likely claimed lives. Water would have reached places that most in Connecticut would have never thought possible. As bad as Sandy was our state really lucked out. The dire message we were trying to get out along with the governor was necessary given the data we were seeing and the potential for a truly unthinkable event. If you need to see how bad it could have been look just to our west in New York or New Jersey where high tide was several hours earlier.

In East Haven, 2 houses were destroyed and 4 houses will likely be condemned. In Fairfield 5 houses were swept out to sea and at least 12 will likely be condemned. Fairfield’s coastal flooding was the worse since 1938. East Haven’s coastal flooding damage fell short of what was seen last year during Irene.

The actual tide leve in East Haven from Sandy was higher than during Irene. The damage, however, wasn’t as bad. Of the 28 homes destroyed during Irene many weren’t rebuilt. The ones that were rebuilt were raised to avoid surge like this. There simply wasn’t nearly as much to destroy on Cosey Beach!

Another issue that gets overlooked sometimes is that the wave action on the coast from New Haven and points east was greater during Irene. Winds were due easterly in Sandy (parallel to the shore) while during Irene the winds were more backed and southerly. A more onshore wind brought even more significant and destructive wave action to the beaches. It’s the wave action on top of a surge that can start eating through a house. In Farifield, due to the coast’s geography, an easterly wind is able to bring higher and more destructive wave action right to the beaches as the wind is more perpendicular to the West Haven to Greenwich coast.

Hurricane Sandy likely produced winds near category 1 strength along the New Jersey coast. Farther north, the storm produced hours and hours of tropical storm force winds including occasional gusts exceeding hurricane force. The worst of the wind occurred when the boundary layer mixed a bit promoting the efficient transport of stronger winds aloft to the surface.

There’s no question the winds were stronger statewide in Sandy than during Irene. However, with the exception of the immediate shoreline, the tree damage from Sandy was less impressive than Irene.

Here is a look at maximum wind gusts in Connecticut from Sandy and Irene.

  • New Haven* – Sandy: 50 mph / Irene: 67 mph
  • Bridgeport –  Sandy: 76 mph / Irene: 63 mph
  • Groton – Sandy: 75 mph / Irene: 58 mph
  • Danbury – Sandy: 68 mph / Irene: 47 mph
  • Hartford** – Sandy: 54 mph / Irene: 46 mph
  • Willimantic – Sandy: 53 mph / Irene: 51 mph
  • Bradley – Sandy: 62 mph / Irene: 51 mph

* No reports at KHVN past 5 p.m. during Sandy
** No reports at KHFD past 7 p.m. during Sandy

There are several reasons for the parity in tree damage from Irene and Sandy in most towns. One reason is that the trees were mainly bare away from the shore! A leafed tree is much easier to knock over than a bare one. Irene also dropped 5″-10″ of rain across Connecticut prior to and during to the strongest winds. Saturated and weakened soil makes it easier to uproot a tree. Another reason is that Irene and the October snowstorm knocked down a lot of weaker trees and limbs. There was less to destroy after the 2011 storms!

Courtesy: Debra Bogstie / NBC Connecticut – Guilford Green lost at least 6 trees with more substantial damage than seen during Irene. Just a mile or two inland, however, the damage from Sandy was less than Irene.

That said, the hurricane force wind gusts from Sandy within a mile or two of the Sound resulted in substantial damage in some shoreline towns. Structural damage, including roof and siding damage, occurred in Sandy and generally didn’t during Irene.

Meteorologically, this was the oddest storm I’ve ever covered. Strangely, it occurred 1 year to the date after the second oddest storm I’ve ever covered.  I’ve never seen a hurricane take the path this one did. Not even close. In the beginning (7 or 8 days out) it was easy to dismiss some of the computer models as they were predicting something that had never been seen before. As time went on the weather pattern became more clear and it was evident that something truly extraordinary was about to happen.

This hurricane made landfall with a pressure of 946mb making this the strongest storm to make landfall in the northeast in more than 70 years.

Sandy was an incredible storm. It will likely change the way coastal residents,  emergency managers, and government officials  in the northeast think about just how vulnerable our coastline is. The northeast has been lucky in the last several decades with a relatively quiet period of tropical activity. History has shown that hurricanes can move onshore here and they frequently do so with disastrous results.

So far it seems the state and the utilities were prepared for Sandy. The response and the preparation, in my opinion, has been impressive from the governor right on down to local officials.

Our work as a state isn’t done. We need to make sure we are prepared for the “big one” because Sandy wasn’t it. In fact it wasn’t even close to a “doomsday” storm like a repeat of 1938.  Let’s take the lessons learned from the last 3 storms and make sure we are ready for the next hurricane.

Special thanks to the Connecticut National Guard, the Fairfield Police Department and the Army Corps of Engineers for pictures and data. 

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10 thoughts on “Sandy Sets Records and Reshapes Coast

  1. So the highest wind guest in New Haven was only 50mph before 5 pm? Doesn’t that seem low. I live on a hill about 1,000ft in New Hartford and my weather station record a 55 mph gust a about 5:15 and had the highest one at 69 at about 7:30. How did i get more wind?

    • At least initially, James, the stronger winds just above the surface were effectively “bottled up” by a weak inversion. That inversion weakened toward sunset and the atmosphere began mixing the strong winds down to the ground. So I wouldn’t be surprised in HVN went from 50 to 65 or 70 mph between 5 p.m. and 6 p.m. but we’ll never know for sure.

  2. Pingback: A Closer Look at Sandy’s Damaging Wind | Way Too Much Weather

  3. Ryan,

    Did this storm break the historical storm tide records as you suggested it might when the storm was approaching? I’m curious about tide levels as opposed to storm surge. Thanks

    Todd

    • Hey Todd. The storm actually did break the record in Bridgeport and tied it in Stamford. What I think is the most important to realize is that the peak tide in Stamford was 11.0 ft and the peak surge was 11.2 feet. Had the peak surge coincided with high tide the peak tide would have been around 17 feet. That would have been beyond devastating and unimaginable for New Haven through Greenwich. The amount of destruction would have been hard to fathom. While peak tide levels were near record levels I think we’ve been lucky in the last 50 years and we haven’t seen a nything close to a worst case scenario. Sandy showed us just how vulnerable we are.

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  5. Ryan, are there any records on rainfall during Sandy in late October 2012 for New Haven or Orange, CT areas? Thanks.

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