Sandy Semantics and Communication Confusion

Screen shot 2012-11-01 at 1.05.19 PM

Prior to hurricane Sandy’s arrival in the northeast the National Hurricane Center decided against issuing hurricane warnings north of the mid Atlantic. Their reasoning was that the storm would be transitioning from a tropical system to a post-tropical storm.

Based on existing policy, once the storm became post-tropical, the NHC would have to drop all hurricane warnings and local NWS offices would need to issue a new set of warnings, statements, and advisories.

This is how the NHC described their decision (which was, apparently, not solely theirs but one coordinated with other NWS/NOAA entities) in their forecast discussions during the day on Saturday.

5 a.m. Saturday NHC Advisory
5 a.m. Saturday NHC Advisory
11 a.m. NHC Advisory
11 a.m. Saturday NHC Advisory
11 p.m. NHC Advisory
11 p.m. Saturday NHC Advisory

I haven’t commented on this decision on the air or on this platform up until today for several reasons. While some media outlets and blogs harped endlessly on the NHC decision to not issue warnings/watches immediately prior to landfall I thought it was best to ignore their decision not to issue, focus solely on the expected impacts, and call the thing a hurricane both on air and on the blog. After the fact, enough had been written about where I didn’t have a whole lot to add!

Far too much time was wasted by some explaining what the storm’s structure would be and what to call the storm during the time people were (or should have been) preparing or evacuating. Frankenstorm (which came from the NWS), superstorm, hurricane, or hurricane inside a nor’easter, etc. When communicating a major, historic, and dangerous weather event wasting any time on semantics is dangerous business. No need to make the message any more confusing than it needs to be!

Following the storm there was near constant chatter in weather circles (including from some in the National Weather Service) about the NHC decision. Very little of it was supportive.

I disagreed with the NHC decision. Strongly. Most tropical storms that impact New England are transitioning to extra-tropical or post-tropical by the time they reach our latitude. A combination of colder water and interaction with the mid latitude jet stream kick starts the extra-tropical transition (ET) process. Most storms (e.g. Irene, Floyd, Bertha, Gloria, etc.) weaken as they undergo ET. Sandy strengthened as it underwent ET.

Extra-tropical transition is not a binary process. It’s a continuum. There’s not switch that gets flipped that tells you “Yup, that’s it, this storm became extra-tropical at 7:33 p.m..” How the NHC knew the storm would be post-tropical with a great deal of certainty Saturday morning (48+ hours prior to landfall) is a mystery to me. While great strides have been made in ET research over the last decade (see research by Hart and Evans), it’s still a challenge to predict.

What made the National Hurricane Center’s decision so confounding to me is that for previous storms that were undergoing ET the NHC maintained them as “tropical” and kept tropical warnings up until the threat diminished for coastal areas. Those were for weakening storms undergoing ET! Why would they do it for a strengthening storm undergoing ET!?

One of the reasons, as mentioned in the NHC discussions on Saturday, was the possibility of the need to change from tropical to non-tropical warnings which, due to the inflexibility of the warning system, would have been time consuming for the already tightly staffed NWS offices and probably confusing to the end-user. The answer that makes the most sense to me would have been continuing to call the storm a “hurricane” until it had moved inland. There’s certainly an argument you could make that the storm was still a “hybrid” system that had both tropical and non-tropical characteristics like so many other hurricanes that impact this region.

Earlier today, Accuweather reported that the National Hurricane Center has already changed its policy for future storms.

An announcement that sustained winds of 74 mph or higher are expected somewhere within the specified area in association with a tropical, sub-tropical, or post-tropical cyclone. Because hurricane preparedness activities become difficult once winds reach tropical storm force, the warning is issued 36 hours in advance of the anticipated onset of tropical-storm-force winds. The warning can remain in effect when dangerously high water or a combination of dangerously high water and waves continue, even though winds may be less than hurricane force.

The National Weather Service, according to the Washington Post, now denies this change has been made and says it’s a proposal that has not been adopted.

Regardless of what actually has occurred the interview with Accuweather by NHC Science and Operations Officer Chris Landsea was surprisingly frank and open.

“Sandy was not ideal, and the way we handled it was not right. But we’re fixing it,” Landsea told AccuWeather.com.

“We realize this was not satisfactory and we want to make it better for next year.”

The post-Sandy discussion, thus far, has been a bit bizarre. The National Weather Service ordered a service assessment to be co-chaired by Mike Smith of Accuweather then suddenly cancelled it (covered extensively here, here and here). Meanwhile, the New York Times reported that some in New York City Mayor Michael Bloomberg’s administration were throwing the National Weather Service under the bus for contradictory forecasts after the shocking decision to leave nursing home residents in their facilities located in flood zones.

Today, according to the Philadelphia Inquirer, NJTransit threw the National Weather Service under the bus as well. Not surprisingly, that’s not sitting well with people at the local National Weather Service offices who did a phenomenal job when, in some cases, they had one hand tied behind their back by the NHC. Here’s how a meteorologist at the Mount Holly NWS office responded to the comments by NJ Transit on Twitter.

Screen shot 2012-12-05 at 8.02.34 PM

I found the National Weather Service forecasts from our local offices (Albany, Taunton, and Upton) to be nothing short of perfect. We worked with them closely through the event and they couldn’t have been better. I’ve heard extremely positive things about the job the embedded National Weather Service incident meteorologist did with the Connecticut Office of Emergency Management prior to and during Sandy. While issuing a seemingly endless number of products, statements, and warnings they were responding to our questions within moments and we worked together to share thoughts and information on storm surge, wind forecasts, and other Sandy related issues. I couldn’t have asked for anything more, particularly from the Upton, NY office.

While the NHC’s decision to not issue warnings muddied the message in some cases, the message from the local National Weather Service offices could not have been any more clear. There were bigger issues than the lack of hurricane warnings, in my opinion. The lack of education and complacency in parts of New York and New Jersey was and is quite concerning. How much did Irene’s relatively minor impact around New York play into that complacency is unclear. How much Mayor Bloomberg’s initial downplaying of the storm on Saturday played into it is also unclear. How about New York City and New Jersey’s hurricane “drought” over the last few decades? Did people think they were “immune” from Sandy’s wrath no matter what the forecasts were?

It appears the NHC is taking steps to rectify their rigid rules and policies to become more common sense and practical. That’s good. Flexibility and removing barriers to effective communication is a good step to improving weather warnings in the future. The much larger issue, however, is figuring out how people best respond to weather warnings. In order to respond to a warning you need to know, and believe, that you’re in a vulnerable place. A warning people don’t listen to isn’t any good.

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.