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Posted at 10:30 AM ET, 07/29/2010

D.C. record snow in 2010 not due to global warming

By Steve Tracton

* Thunderstorms likely today: Full Forecast | NatCast *

Top panel: Global surface temperature trends over the last 50 or so years, courtesy NOAA. Bottom panel: Snow at the Capitol this past winter. By CWG photographer Ian Livingston.

Memories of the record-breaking cold and snowstorms of last winter, including Snowpocalypse, Snowmaggedon and Snoverkill, have probably faded, as eventually will be true of memories of the record-breaking heat this summer. Unless, that is, the extreme winter and summer weather prove to be just a preview of conditions that become the new normal as a consequence of global climate change. Should that prove the case, it might be hard to forget "the good ole days" when the extremes of winter/summer of 2009/2010 were the exception, not the rule.

How likely is that we're entering an age where extremes in weather become the new normal? Personally, I believe the weight of evidence viewed objectively points in that general direction, although there is much uncertainty about details of how, when, where and in what phenomena and parameters extremes will appear and have consequence in human affairs.

In regard to the snowstorms that affected the D.C. metro region and other mid-Atlantic and northeast coastal regions, a new study by a team of scientists at Columbia University's Lamont-Doherty Earth Observatory argues that global warming was not involved. Rather, the study finds the anomalous winter was primarily the result of convergence of an exceptionally strong El Nino and unusually strong negative phase of North Atlantic Oscillation (NAO).

El Nino typically brings wet weather to the southeastern U.S. and enhances the odds for an East Coast storm track, while the negative phase of the NAO corresponds to an atmospheric circulation pattern which brings cold air from Arctic regions into eastern North America. What might be the weather/climate understatement of the year, the authors conclude when these patterns coincide, "end result: more snow".

I'm fully on board with contention that man-made global warming or, more generally, global climate change is not responsible for the past winter's cold and snow. It's certainly possible that, as the IPCC report indicates, increased atmospheric moisture in a warming world generally speaking could enhance precipitation and thereby snowfall amounts where it remains cold enough for snow.

In that context it's possible to argue that the cold and winter snows were consistent with expectations with global warming. But that's a far cry from evidence that necessarily led to, or even tilted the odds toward the major 2009/2010 snow events. Indeed there is nothing to indicate that the convergence in the specific manifestations of El Nino and NAO were anything more than coincidental.

The authors correctly disabuse the irresponsible proclamation of hard-core deniers that the cold and snow last winter is evidence against human caused global warming, not withstanding the fact that globally the winter was significantly above normal. Scientists agree that no single storm or series of storms in any given season affecting any given region are evidence for or against climate change.

Unfortunately for proponents of measures to reduce greenhouse gas emissions, snow buried the "seats of power" in Washington enabling use by some to undermine the political case for global warming and support for meaningful action. Ironically perhaps, the excessive heat this summer apparently has not increased support.

The authors justifiably note, but do not explain that El Nino and negative NAO were not necessarily the only reasons for the past winter cold and snow.

In a previous post, I indicated that the December snowstorm (Snowpocalypse) occurred before the nominal response to El Nino on the Pacific jet and probably sub tropical jet and storm tracks had kicked in. The subtropical jet often acts as a conveyor belt of moisture feeding storms that develop in the southern U.S. which sometimes head northeast towards us independently of El Nino. Additionally, the authors did not consider the likely critical influence of the third ingredient I mentioned, the Pacific North American (PNA) teleconnection - which can help lock in cold air over the East - in setting the stage (and enhancing predictability) for the snowstorms.

In a discussion of the technical study, the authors conclude:

In summary, what happened this past winter is just another example of the kind of seasonal climate anomaly that can arise from purely natural variability of the atmosphere-ocean system. There seems no evidence that it had anything to do with climate change and should not be exploited to make arguments, one way or another, about the reality of that (which we do not doubt) or how to tackle it.

In its press materials, Columbia University quotes Rutgers University climate scientist David Robinson, who says: "When the public experiences abnormal weather, they want to know what's causing it. This paper explains what happened, and why global warming was not really involved. It helps build credibility in climate science."

Mission accomplished? What do you think?

The views expressed here are the author's alone and do not represent any position of the Washington Post, its news staff or the Capital Weather Gang.

Related reading:

The study: Northern Hemisphere winter snow anomalies: ENSO, NAO
and the winter of 2009/10

Causes for Mid-Atlantic Snowstorms 2009/10 (NOAA Fact Sheet, Word Document)

Forensic Meteorology Solves the Mystery of Record Snows (NOAA Climate Watch Magazine)

Research says big snow storms not inconsistent with -- and may be ampliflied by -- a warming planet (Joe Romm, Climate Progress)

New peer reviewed paper refutes claims of blizzards of last winter being driven by "global warming" (Anthony Watts, WattsUpWithThat Blog)

Expert: Blizzards "consistent with" climate change
(Andrew Freedman, Capital Weather Gang with Jeff Masters, Weather Underground)

By Steve Tracton  | July 29, 2010; 10:30 AM ET
Categories:  Climate Change, Science, Snowmageddon, Tracton, Winter Storms  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Forecast: Storms today no match for last Sunday's
Next: Strong thunderstorms slowly moving southeast


Dr. Tracton,

You are missing a word in this sentence -
"Scientists agree that no single or series of storms any given season affecting any given region are evidence for or against climate change." No single storm?

Did you see the study about rapid melting of the Arctic sea ice being caused by soot and not global warming?

Have you seen the NASA study about the vulnerability of our electric grid, specifically our transformers, to solar flares? Holy smokes! Tens of millions without power, possibly for years. Can you imagine such a thing?!?! No refrigerators. No computers. No television. No air conditioning. Hospitals running solely on backup power. No electronic cash registers. No running water. Water treatment facilities rely on pumps, which need electricity to operate. No nothing. A lot of your readers advocate a low carbon footprint lifestyle. Let's hope they don't get to see what a real low carbon footprint looks like when imposed upon entire cities and states.

Mr. Q.

Posted by: Mr_Q | July 29, 2010 11:25 AM | Report abuse

@Mr. Q

Thank you for pointing out the missing word(s). Fixed.

Posted by: CapitalWeatherGang | July 29, 2010 11:42 AM | Report abuse

Soot is a manmade contributor to global warming, but it is distinct from carbon dioxide.

Steve - I find the title of this piece to be slightly misleading. This study concluded that the storms were likely unrelated to climate change, but the way it is worded is too definitive. You need a ", study says" to qualify it, in my view.

Also, how would you respond to Joe Romm's criticism of this study - specifically that it glossed over related studies that might contradict its findings?

Posted by: afreedma | July 29, 2010 11:44 AM | Report abuse

Mr. Q

Thanks for noticing the missing word (storm).

The issue of the vulnerability to solar storms has been one I've continually tried to point out here and elsewhere over and over again. I'm totally with you on this!

There is a lot more to this. One of the most depressing aspects is that the danger and consequences are not even on the radar screen of DHS. If you (or anyone else) would like to become active and pursue this further, get in touch with me at my offline email

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 11:56 AM | Report abuse

afreedma wrote, "Soot is a manmade contributor to global warming, but it is distinct from carbon dioxide."

Obviously soot is distinct(ly different) from carbon dioxide. That was the whole point.

Soot has been shown to significantly contribute to melting ice, all ice, but I think melting ice is distinct from global warming.

afreedma also wrote, "Also, how would you respond to Joe Romm's criticism of this study - specifically that it glossed over related studies that might contradict its findings?"

I don't pay any attention to Joe Romm. And I am really, really, really, REALLY SICK of the use of the qualifier "might". You could say might about anything. Did Joe Romm really say "might contradict"? If he did, why did he say that? Why can't he look at the other studies and say definitively whether or not they contradict this new study?

I personally think qualifiers like "might" are often used to intentionally obfuscate/hide the truth. Just my humble opinion.

Mr. Q.

PS. I hope this doesn't double post. I received a time out error on my last attempt.

Posted by: Mr_Q | July 29, 2010 12:09 PM | Report abuse

Andrew The title is essentially my long held belief, and I'm taking the opportunity of the new study to support it.

I'll read through Joe Rhomm's criticism again, but it seems to me that he and his references are much too general, as is what I referred to in regard to increase moisture in a warming world. Nothing as I see it is specific to the particulars of the snowstorms hereabouts last winter. What occurred did not require global warming, even to tilt the odds in the directions we saw.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 12:11 PM | Report abuse

so the blizzards were "the result of convergence of an exceptionally strong El Nino and unusually strong negative phase of North Atlantic Oscillation"

so what was the cause of the exceptionally strong el Nino, and the cause of the unusually strong negative phase of the N Atlantic Oscillation?

Posted by: MarilynManson | July 29, 2010 12:18 PM | Report abuse

Dr. Tracton,

You are welcome for the catch.

Dr. Tracton wrote, "I'm totally with you on this!"

This is too cool! We finally agree on something.

Politicians/governments always baffle me. I personally think a solar storm of the magnitude referenced in that NASA study is just a matter of time. Not a question of if. A question of when. And we KNOW what needs to be fixed in our electric grid to avoid the almost certain anarchy and mass death. It is a SIMPLE fix! But they aren't doing a thing about it. Instead they want to usurp more power and money from the people to combat climate change?!?! Argh!!!!!!!!

Maybe if the ruling class could figure out a way of getting more power and money, they would be interested in tackling the vulnerabilities in our power grid.

I'll send you an email later today. I have to run right now.

Mr. Q.

Posted by: Mr_Q | July 29, 2010 12:22 PM | Report abuse

With all due respect, I think it's irresponsible to present a longheld personal belief as unqualified fact. I believe that your last post, on whether climate change contributed to the earthquake, was wildly speculative and based on very circumstantial evidence - with the result that, as here, you were presenting a very misleading and blurry version of the science. In addition, the references here were to other blogs - and a link to a link to isolated study in question - which is hardly conclusive evidence.

I don't know what to believe in this particular case, but it's misleading to suggest based on the evidence you do provide that readers can draw a conclusion. This entry is just another reason that blog posts should be taken with a grain of salt...and another reason that the whole debate over climate change is riddled with misinformation and half-truths presented as facts.

Posted by: paperball | July 29, 2010 12:28 PM | Report abuse

I'm amused by those that insist the recent winter storms disproved AGW.

I'm further amused by those that insist the recent heat waves are further proof of AGW.

Guess what? Neither are proof of anything.

None of you bozos trying to prove one case or the other have enough data to define what is above or below average.

Attempting to define the average is an INTRACTABLE problem. The earth is MILLIONS of years old, but you only have enough reliable data for the past few decades.

It's like measuring the average high & low temperatures for one day and extrapolating it to be the yearly averages.

So, can we please move on to REAL environmental problems? For example, heavy metals or traces of prescription drugs in our water supply.

Posted by: HughJassPhD | July 29, 2010 12:52 PM | Report abuse

Re: "The earth is MILLIONS of years old..."

That reminds me of when Dr. Evil was holding the Earth hostage for "one MILION Dollars!!!"

Posted by: GD1975 | July 29, 2010 1:08 PM | Report abuse


exceptionally strong el Nino and unusually strong NAO, yes, but not unprecedented and within the range of natural variability exclusive of climate change.

While there are commonalities from one El Nino to another, there are various flavors, so to speak, on the details of how the effects of El Nino (warm tropical Pacific waters) register on the atmosphere.

The unusually strong NAO might very well be a consequence on the manner it is calculated. The high latitude blocking highs which collectively contribute to the strength were likely oriented in time and space to yield an unusually large value of the NAO index.

There is no known connection between El NIno and the NAO. The particular manifestation of each in just the right way were, in my opinion, the primary responsible agents for the last winter's snowstorms - all as a matter of chance, i.e., the chaotic and essentially unpredictable nature of the atmosphere/ocean system.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 1:18 PM | Report abuse

Do you know what Science is? Do I need a 6th grader to teach you how this is due to CLIMATE CHANGE not Global Warming. Stop watching fox news and the view and read some Journals from actual research. You should be fired on the spot, without question. Plenty of unemployed College Grads would love to have your position.

Posted by: MajorFacemask | July 29, 2010 1:28 PM | Report abuse


You are misreading this post if you believe I'm suggesting anything as an unqualified fact. The earthquake/ice melt post was clearly speculative, as you acknowledged. This post is far stronger in expressing a belief that has significant backing with empirical evidence and science based reasoning (not speculation).

I' open to any comparable contradictory evidenced based reasoning on the specifics, not grand scale generalities, of the DC snowstorms.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 1:33 PM | Report abuse

"There is no known connection between El NIno and the NAO. The particular manifestation of each in just the right way were, in my opinion, the primary responsible agents for the last winter's snowstorms - all as a matter of chance, i.e., the chaotic and essentially unpredictable nature of the atmosphere/ocean system."

So when your limited knowledge of science fails to explain something, it can all just be given to "chance".

In other words, you just don't know.

Posted by: MarilynManson | July 29, 2010 1:44 PM | Report abuse

Years ago the IPCC posted a summary of the expected effects of global climate change which they called "thermal forcing". In a systems approach to the problem, their most memorable prediction was that our climate will experience "greater oscillations" that will "exceed the end points" (meaning the highest and lowest temperatures and precipitation and wind speeds we are used to), as the climate seeks a new equilibium point. Whether soot from exhaust or methane from arctic peat adds to the problem, the base mechanism of rapid temperature (7F or 4C) and sea level (tens of meters) rise is now being forced until we actually lower the global CO2 level below the baseline of 290 ppm, which has been the MAXIMUM CO2 level ever reached for the past 400,000 years (see the annotated climate graph on our homepage thanks to Dr. Jim Hansen)on our planet. However, CO2 is now pushing 390 ppm and climbing. Plankton restoration to the oceans is a quick, short-term fix until we supplant all fossil fuel usage with clean energy. For more info, buy "Storms of My Grandchildren" by Jim Hansen, the most courageous climatologist in the world.

Posted by: IntegrityResearchInstituteorg | July 29, 2010 1:53 PM | Report abuse

There has been significant action recently to respond to the threat of solar storms on the electrical grid. This ClimateWire story covers the major developments

In June, the Space Weather Enterprise Forum convened experts to discuss the solar storm threat.

In July, The North American Electric Reliability Corp. and Department of Energy issued a 100-page report detailing the threats and recommended responses.

The US House passed H.R. 5026, the "Grid Reliability and Infrastructure Defense Act," or "GRID Act," authorizing emergency measures to protect power transmission networks.

Senate committees, Commerce and Homeland Security, have reported out bills for grid security. Energy and Natural Resources is also working on it. Rep. Bennie Thompson, chair of the Homeland Security Committee said the goal is a completed bill by the end of this year.

Posted by: fakedude1 | July 29, 2010 1:53 PM | Report abuse

Thanks for the reply. I don't think I'm wrong about the headline's suggesting unqualified fact, though, and your science-based reasoning seems to rely on only one article describing a peer-reviewed article - too weak a standard to draw the conclusion you made, in my humble opinion. The issue of climate change attracts both copious evidence and copious speculation, and I still don't believe it helps matters to confuse the two, especially when most readers won't know the difference and will rely on your authority as a writer for the Post.

Thanks for listening!

Posted by: paperball | July 29, 2010 2:04 PM | Report abuse


It's true I and probably no one else knows because somethings just cannot be known with complete certainty in theory and in practice.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 2:05 PM | Report abuse


Thanks for the input. If you haven't become aware of this yet, you and Mr. Q are hitting one of my really hot, hot buttons. Although off topic, I'll respond.

As you indicate there are at least discussions and prospective bills being considered. But, as the link you provided indicates, cost issues will likely stop anything meaningful in its tracks. So what else is new!

There is a distinct, if not especially likely threat of debilitating solar storms over the next few years as the next solar max reaches it's expected peak in 2012-2013. But, as the BP debacle demonstrates, low probability but very high impact events can have dire consequences.

A solar storm could have effects orders of magnitude beyond anything you might conceive short of a nuclear war (see: Do Solar Storms Threaten Life as We Know It?

Not being prepared for such an event is totally irresponsible, whether by private industry of government - especially when engineers already know how to mitigate the vulnerability. The cost of becoming prepared is pocket change compared to the costs of dealing with the disaster after it occurs. And this protection should be incorporated into the country's power grid exclusive of solar activity, since the grid is vulnerable to other sources of major disruption.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 2:47 PM | Report abuse

"For more info, buy "Storms of My Grandchildren" by Jim Hansen, the most courageous climatologist in the world."

"Courageous" is not the term I'd use for a legitimate & credible scientist.

However, the term is an appropriate accolade for a wild eyed ideologue.

Posted by: HughJassPhD | July 29, 2010 2:49 PM | Report abuse

"It's true I and probably no one else knows because somethings just cannot be known with complete certainty in theory and in practice."

There are many things in daily life that we do not "know with certainty". And this is when we turn to stochastics to at least quantify the uncertainty.

And stochastics teaches us that the larger the data set the higher the reliability of the estimate (ie average temp) of a process (ie weather).

And right now our data set is way too small to properly characterize the weather. To do this we need reliable data from all over the world going back a very long time. And we currently do not have this data. We are not even close. And we are not going to have this data for many lifetimes.

So everyone step back from your scrutiny of El Nino, ice cores & sun spots and take a deep breath. You're missing the big picture. You're trying to solve an intractable problem.

Posted by: HughJassPhD | July 29, 2010 3:14 PM | Report abuse

If one receives death threats, as James Hansen and other climate scientists have,
and keeps on, that is courageous. If one faces political persecution from powerful officials, as Michael Mann and others have,
and keeps on, that is courageous.

The claim about soot is that it is second in importance to carbon dioxide. The good news is that soot is much easier to deal with than carbon dioxide.

It seems to me that we need to consider all threats and think carefully of how to deal with them. Solar storms is one such threat and global warming is probably another. There are also possible threats such as acidification of the ocean that need to be studied.

It seems to me that last winter's storms do not require global warming for an explanation, but it would seem extremely difficult to prove definitely that global warming was or was not involved.

Posted by: Dadmeister | July 29, 2010 3:27 PM | Report abuse

I read an interesting article recently on how SUNSPOTS might actually be contributing to our bizarre weather:

Posted by: undercover_hon | July 29, 2010 4:56 PM | Report abuse

I cannot, nor can anyone I believe, prove that global warming was not responsible for the snowstorms, or was the phase of the moon, or a passing asteroid, or spaghetti monster, or a remnant of the Big Bang, or a manifestation of string theory, etc., etc., etc.; But, neither can it be proved conclusively that it was.

What's important are the rational, scientifically sound and plausible possibilities (hypotheses) that can reasonably be applicable to a specific question. Hype and bias whatever the issue should never be a factor. I may be wrong with what I believe is a very low probability, but would praise the science if it were convincingly demonstrated that the odds were reversed (odds, since complete certainty is impossible).

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 5:21 PM | Report abuse

Well, an interesting comparison will be next winter. There is a La Nina forming in the Pacific, which, if memory serves, provides a drier, colder East Coast winter normally. If there's a La Nina and we still have some monster snow storms, then I think this theory will need to be reworked a little.

Posted by: oldtimehockey | July 29, 2010 5:29 PM | Report abuse

Actually, I'm pretty sure the Flying Spaghetti Monster was responsible for the snowstorms. The Greater DC Area was touched by His Noodly Appendage.

As for the heat waves, who knows. That ain't how FSM rolls.

Posted by: btd_ | July 29, 2010 5:47 PM | Report abuse

Dadmeister says "It seems to me that last winter's storms do not require global warming for an explanation, but it would seem extremely difficult to prove definitely that global warming was or was not involved."

Why try to prove absolutes? Just figure out whether increased CO2 can cause bigger snowstorms. The theory of CO2 warming is to reduce temperature differences between cold dry places (where CO2 warming has an effect) and warm wet places (where it has very little effect if any). There would simply be less cold air to feed the snowstorms. It is therefore a pretty good bet that CO2 warming was not involved.

Posted by: eric654 | July 29, 2010 5:59 PM | Report abuse


We've had a number of "monster snowstorms" during La Nina (and neutral) winters. El Nino increases the odds of a "big one", but it is not a necessary nor sufficient condition. Another way to say this is that El Nino like conditions can develop independent of an actual El Nino.

The reverse is also true; there are (too many) winters without a biggie even during El Nino years. The devil (chaos, butterfly effect) is in the unpredictable details.

Posted by: SteveT-CapitalWeatherGang | July 29, 2010 6:00 PM | Report abuse

If one looks at the recent State of the Climate 2009 by NOAA and the Met Office, it is fairly certain that global warming is occuring and that atmospheric water vapor has increased. The greater amount of water vapor could contribute to more snow than otherwise.

Also, if the Arctic is warmer than normal, could it be due to less sea ice than normal and thinner sea ice than normal? Would this reinforce the NAO (or Arctic oscillation (I don't really know the exact distinction between; I believe they are well correlated) and produce higher heights over the Arctic and lower heights over the eastern US?

Admittedly this is a wild hypothesis, but I feel like indulging myself...

Steve is quite right that the events could well have nothing to do with global warming, but I still feel that global warming may have contributed to intensifying the storms.

There are certainly much clearer effects of global warming.

Posted by: Dadmeister | July 30, 2010 9:19 AM | Report abuse


The NAO is the dominant mode of winter climate variability in the North Atlantic region ranging from central North America to Europe and much of Northern Asia.

The AO includes the corresponding variability over the northern Pacific. They are highly correlated as you say, and for purposes here considering just the NAO suffices, though there would be no difference in conclusions if the AO were invoked.

In winter, the Arctic is now still completely ice covered and therefore probably does not affect temperatures in the Arctic from the norm. Warmer winters must be due to something else and global warming is the justifiably prime suspect.

You raise an interesting question on what would happen if much of the Arctic ocean were largely ice free even in winter. Probably a lot, I believe. It would have significant effects on the now usual source of cold air outbreaks. Just as importantly, there likely would be considerably more cyclone (storm) activity in the form of polar lows given the contrast between the relatively warm Arctic waters and cold interior. Storms can have a key role in development of blocking highs, which in turn would affect the NAO. Just how, when and where, as far as I know, is questionable. Take all of this as informed speculation.

Posted by: SteveT-CapitalWeatherGang | July 30, 2010 9:40 AM | Report abuse

Perhaps natural cycles are at work here. Let's examine this theory. In late January 1922, we had 28 inches of snow with the Kickerbocker Storm, still the greatest single storm amount in DC. In 1966, we had the "Blizzard of 66" in late January. And in 2010, we had the back to back snowstorms in late January-early February. 44 years seperates all those years. And this summer being so hot could have been easily predicted. Take a look at the record highs for Dulles for July. 12 of the 31 days have records in the "11 year solar cycle" years (1966, 1977, 1988, 1999, 2010). If we consider all these, this should have been a year of extremes. And I don't know why, but I have this feeling a tropical system is going to affect us around September 15th. Let's see how that turns out. No doubt it's been a fun year if you're a weather geek like me.

Posted by: cloudking1 | July 31, 2010 12:20 PM | Report abuse

Sorry cloudking1, I don't get how you come up with this summer's heat and year of extremes should have been predicted

The snowstorms you cited and (I'll take your word for it now) the temperature records for July at Dulles occurred in the "11 year solar cycle" - your not specific, but it appears you must be speaking of years of solar minimum. But, a majority of big snowstorms and high temp records do no coincide with solar minima.

Posted by: SteveT-CapitalWeatherGang | July 31, 2010 4:44 PM | Report abuse

I just looked at the climate data, and it's actually 13 days Dulles had record highs in those years (1966, 77, 88, 99, 2010). I'm convinced there's a link between the solar cycle and hot summers every 11 years. As far as last winter, I don't think the solar cycle had a major part in that. I just think it's an interesting coincidence (perhaps not?) that those snowstorms all occurred 44 years apart.

Posted by: cloudking1 | July 31, 2010 5:20 PM | Report abuse

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