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Sandy’s Surge Was NOT Unexpectedly High

October 31st, 2012 - 12:31 pm

An Associated Press story this morning propagates a total falsehood that’s gaining in currency:

With all the planning, and all the predictions, planning big was not big enough. Superstorm Sandy went bigger [than previous storms] — a surge of 14 feet.

“Nobody predicted it would be that high,” said ConEd spokesman Allan Drury.

[FRIDAY UPDATE: Mayor Bloomberg has now repeated the same claim, asserting that "no one expected" a surge as high as what occurred.]

THIS IS UTTERLY, COMPLETELY AND DEMONSTRABLY FALSE. The Associated Press must issue a correction and retraction immediately (as basically the entire story is premised on the falsehood), and the journalistic repetition of this factually incorrect statement needs to stop NOW.

First of all, Sandy’s “surge” in NYC was not 14 feet; it was 9 feet. 14 feet was level of surge + tide. More on that in a moment.

Secondly, the storm surge that occurred — 9 feet — was predicted, well in advance, by the computer models and the National Weather Service and countless others. In fact, you need look no further than this blog’s wee-hours Saturday morning update, titled in part “NYC In Peril”:

[W]e could be looking at a 6-10 foot storm surge in NYC, plus astronomical high tide — as opposed to the 3-5 foot surge in Irene — if Sandy slams New Jersey from the east.

Did you get that? A 6-10 foot storm surge plus high tide? That’s what I wrote at 1:08 AM Saturday, more than 64 hours before landfall.

The “plus high tide” part is critical. To explain why, let’s go over some terminology. Here are NOAA’s definitions of the terms storm surge and storm tide:

Storm Surge: An abnormal rise in sea level accompanying a hurricane or other intense storm, whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic tide from the observed storm tide.

Storm Tide: The actual level of sea water resulting from the astronomic tide combined with the storm surge. Most NWS flood statements, watches, or warnings quantifying above-normal tides will report the Storm Tide.

To repeat: the “storm tide” is the total water level, caused by the “storm surge” plus the regular (“astronomic”) tide.

Sandy’s storm tide (or total water level) was 14 feet because the 9-foot storm surge peaked at high tide — and Monday’s high tide at Battery Park was to be 5 feet even without any surge. Now, remember those definitions. 5 feet is “the level that would have occurred in the absence of the cyclone.” 14 feet is “the astronomic tide combined with the storm surge.” 9 feet is the storm surge alone. 9 + 5 = 14.

This is no mere semantic distinction. It completely obliterates the entire notion that Con Edison, or Mayor Bloomberg or anyone else, can reasonably claim they were unprepared for a “14-foot surge” that was higher than anyone predicted. Here’s what the National Weather Service predicted at 11:23 PM Saturday, almost 48 hours before the storm hit:

TIDAL DEPARTURES…1 TO 1 1/2 FT ABOVE ASTRONOMICAL TIDES SUNDAY NIGHT…2 TO 4 FT ABOVE ASTRONOMICAL TIDES MONDAY MORNING…AND POTENTIAL FOR 5 TO 10 FT ABOVE MONDAY NIGHT INTO TUESDAY MORNING. THE HIGHER END OF THE RANGE RELEGATED TO THE MOST FLOOD PRONE COASTAL LOCATIONS.

So the National Weather Service predicted, as of Saturday night, a storm surge of 5 to 10 feet “above astronomical tides,” with the higher end of the range (closer to 10 feet) quite possible in New York Harbor specifically. Since astronomical high tide is 5′, that means NWS was necessarily predicting a potential storm tide of 10 to 15′ if the surge happened to arrive at high tide, which was obviously possible. (Hence the widespread pre-storm concern about “astronomical high tides” making matters worse.)

The NWS forecast was revised upward at 1:29 PM Sunday:

TIDAL DEPARTURES…BETWEEN 2 TO 3 FT ABOVE ASTRONOMICAL TIDES [SUNDAY NIGHT] DURING HIGH TIDE WITH LOCALLY HIGHER VALUES…3 TO 4.5 FT ABOVE ASTRONOMICAL TIDES MONDAY MORNING…AND POTENTIAL FOR 6 TO 11 FT ABOVE MONDAY NIGHT INTO TUESDAY MORNING. THE HIGHER END OF THE RANGE RELEGATED TO THE NEW YORK HARBOR…WESTERN LONG ISLAND SOUND AND THE LONG ISLAND SOUTH SHORE BACK BAYS.

So, roughly 30 hours before landfall, that’s a prediction of a storm surge 6 to 11 feet “above astronomical tides,” again with the higher end of the range (closer to 11 feet) possible in New York Harbor.

To review:

New York Harbor got a storm surge 9 feet above astronomical tides.

Forecasters predicted a storm surge 6 to 11 feet above astronomical tides, leaning toward the higher end of the range (i.e., 9 to 11 feet) in New York Harbor specifically.

And these people have the audacity to claim “nobody predicted” the surge that occurred?!?

Any public official who says the surge was “unexpected” or higher than predicted is either criminally incompetent, or blatantly lying, or both.

(More information and outrage after the jump.)

(Incidentally, if you’re wondering about even earlier predictions, the predicted range as of Saturday afternoon was a 4-8′ surge. That’s still enough to seriously flood the city (“only” ~5′ to ~5.5′ at high tide was needed to do that) — which is why Bloomberg should have ordered the evacuation of Zones A and B on Saturday — but it’s not quite as high as the 9′ surge that ultimately occurred. Going back a little further, to the Saturday wee hours when I composed my earlier-quoted blog post, the official NWS forecast was for a surge “2 TO 3 FT ABOVE ASTRONOMICAL TIDES…WITH POSSIBLE HIGHER DEPARTURES DEPENDENT UPON THE TRACK OF SANDY.” My citation of 6 to 10 feet in my “NYC In Peril” post was based on computer model estimates of those “possible higher departures” in the event of a worst-case track, as conveyed to me by Eric Holthaus of the Wall Street Journal.)

Here, by the way, is a tweet I posted Saturday night, which also made clear that the forecast was for 6 to 11 feet plus high tide on top of that:

And yet Con Edison says “nobody predicted” a 9-foot surge plus high tide. And the Associated Press repeats that lie without comment or correction.

What’s really strange is, I don’t think ConEd has done anything wrong with respect to its handling of the storm. Of course Sandy was going to produce widespread power outages, and of course it’s going to take a while to get the power back on. As of now, there’s really nothing to criticize the power companies over, so far as I’m aware. And yet ConEd is making complete factual misstatements in its CYA statements. I have no idea why they feel the need to do that — but this false “unexpected” meme must not be allowed to take hold.

Let me repeat what I said repeatedly before the storm hit, and have been emphasizing ever since:

Sandy was an extraordinarily well-forecasted storm (and thank goodness for that), and what it did is precisely what had been forecast for many days in advance by the computer models and the National Weather Serice. There was absolutely no reason for anyone to be surprised, and you should not tolerate CYA excuses — from anyone — that claim otherwise. Again, I encourage voters and citizens to treat all such “caught us off guard” statements as, effectively, letters of resignation by the officials making those statements, because anyone making such a statement is — necessarily — either lying to the public about a matter of critical importance, or was so woefully unprepared and uninformed about the nature of Sandy’s threat that they do not deserve the public trust.

As for you journalists: Do not repeat this lie. Do not allow officials to get away with it. Correct it every time it is stated. Shame those who state it. This cannot be allowed to continue. It is an affront to the notion of public accountability and transparency, an insult to the meteorologists who predicted this storm so well, and above all, a fraud on the American public, to pretend that Sandy’s wrath was “unexpected.”

You are the Fourth Estate. Your job is to inform your readers and viewers about the facts. Do your damn job.

P.S. Please note, this is not about me. I’m not beating my chest or trumpeting how right I was. What I wrote was obvious and well-known; I was relaying information from forecasters, not making “predictions” of my own. It was widely predicted that a surge like this could happen, and indeed, was expected to happen if Sandy stayed on track. So I’m not bragging about how I got it “right.” I’m merely using my statements as an example of how widely well-understood it was — among those paying attention to the computer models and the official NWS predictions, anyway — that a 6-11′ surge on top of the tides was potentially in the offing.

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