December 15, 2013

Are Storms Getting More Intense Over the Pacific Northwest?

It is rare to have a week go by without a local media outlet doing a story suggesting that storms are getting worse in our area, with global warming being the suggested cause.  For example, last month KING-5 ran a story saying exactly that (see image), quoting from a representative of  the National Conservancy.

And this is not the only example of claims that Northwest storms are strengthening.

The sad thing is that these claims of increased storms in our region are simply not true, contradicted by the both observations and the peer-reviewed literature.   The "experts" quoted are often representatives of well-meaning, but poorly informed, advocacy groups.

All too often, the media is failing to do their homework in checking out the veracity of these claims.    So let's do the homework for them!  Let's look at key observations to see if there are any trends in storminess in our region.

First, what about winds?   With the help of UW's Neal Johnson, we have found the maximum winds observed each year at a number of Northwest locations.  Below you will find the plots of annual maximum winds for Astoria and Seattle-Tacoma Airport ... the others are very similar.  There is absolutely no evidence of an upward trend in wind speeds.  In fact, there seems to be a decrease at Seattle-Tacoma Airport.

To really ensure we got the story right, we next found the lowest pressures observed each year at various stations.   The lower the pressure, the stronger storms are in general, so if storms were getting more intense we would expect to see a drop in extreme pressures each year.

Below are the extreme low pressures observed each year for Astoria and Seattle-Tacoma Airport.  Do you see a trend?  I don't.  No hint that storms are getting more intense around here.  You might even come to the opposite conclusion from the pressures at Seattle-Tacoma Airport, that storminess is decreasing.

Are storms getting stronger around here?  The results above do NOT support that conclusion.  And there is a lot of corroboration for doubting the increase.  For example, the comprehensive analysis of Northwest windstorms by Wolf Read (information here) clearly shows that the strongest windstorms on record occurred in 1962 (Columbus Day Storm), with the other big ones in 1880, 1921, 1934,  and 1951.  There is NO evidence that storms are getting more powerful in the Northwest from his work.

Recently, an article in Science Magazine suggested that precipitation/flooding in our mountains are decreasing due to a weakened jet stream approaching the region (see below).  Weakened jet streams would suggest weaker storms, since the wind and temperature gradients associated with the jet stream provides the energy for midlatitude storms.

You can tell I am a bit frustrated by the incessant claims that global warming is already having a big influence on storms and adverse weather here in the Northwest.   

Neither observational evidence nor theory supports such claims. 

Global warming is a very serious issue and later in this century the effects will probably be profound for many regions.  For us, the largest impact will probably be a serious decline in snow pack and the ending of skiing at Snoqualmie Pass.  But exaggerating current impacts when observations and the science say otherwise will only lessen the credibility of the scientific community.  Environmental advocacy groups mean well, but they must understand that crying wolf is not a useful approach in the long run.  And media folks need to vet the claims better.


  1. Speaking of Snoqualmie pass, what's up with this late start?

  2. Doesn't take a scientist to figure out that our storms aren't getting worse....Just more of the media hype! Thanks, again, Cliff for keeping it real!

  3. unless it doesn't get warmer

  4. Is the claim of "highest tide ever in DEC 2012 factual?

  5. The media's job, unfortunately, is to sell viewers to their advertisers, not to inform the viewers.
    Hype is their tool. No news is bad news for them.
    It's like before the Iraq war, the media wouldn't even acknowledge the people calling BS on the WMD's and official "intelegence".

  6. Do you see a trend? I don't.

    I don't disagree with the subject of this post. However isn't there a tool called "statistics" that is a little more accurate than asking your readers to eyeball trends (or lack thereof) from noisy time series?

    1. What are you talking about. He uses the very tool of "statistics" through Scatter Plots to give us a clear idea of what he's talking about. Then he asks us if we see a trend so we know how to view the graph and understand his point as clearly as possible. It's a noisy time series, but thats exactly the point. There is no trend and with it no proof of weather becoming more extreme.

  7. Great post, Cliff. The misrepresentations and exaggerations make it difficult if not impossible for many to hear & accept the truth. As an aside, I'd venture to say that most older, long-time citizens of north Whatcom County would most definitely *not* support the idea of worsening storms. On the contrary, they speak of far more frequent and severe weather events in the past and comment with wonder at how mild the weather seems now, comparatively. Granted, memories can be wonky when it comes to weather, but interesting nonetheless, I think.

  8. Great Article Cliff!

    And your later conclusion about snow I think is also bang on and is being borne out in the data already at low elevations.

    I did a bunch of digging through my local weather records and have found that snow amounts have decreased dramatically at sea level over the past 30 years.

  9. It certainly is getting warmer and the past 20 years have been wetter. See:

    Less extreme cold in the winter for sure:

  10. Cliff:
    You first say that it "is rare to have a week go by without a local media outlet doing a story suggesting that storms are getting worse in our area" and to support that you show a webpage that has a headline about future changes not current changes. Rather than focusing on the primary message of the story - that warming will increase storm intensity in the future - you pick one sentence from an NGO representative about current changes as something you need to debunk.

    Since you provided only a screenshot of the King 5 Environment NW webpage, your blog readers would be unaware that the article also has comments from a UW researcher who is studying decreasing Arctic ice and mentions that reduction in sea ice extent could be affecting lower latitude storms.

    Your focusing on the comment from the person from the Nature Conservancy (which you refer to as the National Conservancy) does little to inform your readers about an important issue. It would be useful if you could now provide a link to the original King 5 story - and maybe some to the other stories you say are coming out on this issue almost every week.

    While the King 5 story may be flawed, its stated intent - to tell the public about the link between warming and future storm intensity - is something you need not misrepresent.

  11. John,
    I don't think I am misrepresenting it. My point is that there is no historical trend over the past half century in the intensity of NW storms. I could have picked other examples from the media and NGO press releases that make this claim. And there is really no convincing modeling or theoretical results to suggest that our local storms will get more intense in the future...cliff

  12. Cliff
    I guess the bigger question is why an academic like you would rather deal with the media and advocacy NGOs and not other academics.

    Why not counter (or even cite so your readers know about it) the work done at Oregon State on how extreme waves are up dramatically in the Pacific Northwest?

    Wouldn't that be more appropriate than latching on to a comment from an NGO staffer or citing a study on precipitation in the mountains that has nothing to do with coastal storm severity?

    As anyone who has been part of the climate change debate can tell you, one needs to ignore the agenda-driven arguments and claims of industry and some NGOs. You would do your readers a service by sticking to the science. There is more than enough there to keep one engaged intellectually.

  13. Chrisale: A Nice link but I'm not convinced. I mean no offensive but making broad statements, about small changes, over very small periods of time is not evidence. It's an observation.

    Look at this link to NOAA and you can see that snow has increased over the last decade. So obviously
    snow is not decreasing. Right?

    Cliff might be right. I hope not but perhaps we won't be skiing at the Summit in one hundred years. I don't care what happens one hundred years from now because I will be long dead, I am bummed about the lack of snow at the Summit this year.

    Maybe this has nothing to do with AGW but is just a result of climate change produced by good ole Mother Earth. I'm just saying because if you didn't know it's been snowing Cairo Egypt.

    "Rare snowfall shuts down Jerusalem, blankets Cairo"

  14. John...the answer to that is clear. The public does not read the refereed technical literature. They get their information through the media. If folks are being misinformed by the media than one must use a form of communication that the media and many people follow (e.g., blogs like mine). I am providing folks with facts and logical arguments. Let the public evaluate them directly. I believe a public discourse of facts are a good thing..cliff

  15. It's odd that you state, "You can tell I am a bit frustrated by the incessant claims that global warming is already having a big influence on storms and adverse weather here in the Northwest." and then you go on to cite a Science paper that shows that global warming has affected storms and adverse weather in the Northwest.

  16. I also believe a public discourse of the facts is a good thing but I am surprised that you have not addressed the primary flaw in your criticism of the comment by the Nature Conservancy staffer. You critique that person as being “well-meaning, but poorly informed” but ignore the fact that there is published research that backs up his concern that coastal storms will get more intense and that there is already evidence for increasing intensity (as I cite in an earlier post).

    You may disagree with the findings of the researchers from Oregon State that demonstrate maximum swell height increasing but their paper is more relevant to the public discourse you initiated on coastal storm intensity than the graphs you provide or the paper on decreased precipitation in the mountains that you mentioned.

    I come to this blog for a discussion of facts about the weather and climate and hope that in some later post you will address some of the findings that either document or predict increasing storm intensity and tell us why you find them credible or not. The Oregon State paper would be a good place to start.

  17. unknown... why do you say it is odd? I wanted to show that there are differing viewpoint in the published literature. In fact, I have a lot of issues with that paper..cliff

  18. John Franklin,
    You need to understand what I am saying in this blog. I am saying that the claims that NW storms OVER THE NW are already getting more intense is false. Period. I know about the Oregon State results (regarding waves)...but that is clearly due to changes in storm offshore and probably far offshore. Not relevant to my analysis. And you are not correct in stating that the literature suggests stronger storms over the NW due to global warming. Can you site any publications that support that? ..cliff

  19. "He uses the very tool of "statistics" through Scatter Plots"

    Jack there are actually statistical tools to test whether a timeseries has a trend or not. Often the eyeball approach is correct, but not always. To be clear: I am not claiming that any of the graphs Dr Mass showed have statistically significant trends. It's just that when I come to a science blog I expect a little better than "Doesn't look like a trend to me."

  20. Codetalker: no offense taken, but I would submit that a 40% drop in snowfall since 1960 at or near sea level in the Alberni Valley is neither small, nor short term.

  21. Appreciations to those who posted links to papers on the science. I did some followup reading which helped me develop a fuller picture of the topic. I have been following the arctic amplication/rossby wave research for several years now and look forward to seeing where the science ends up.

    I am someone who reads the scientific literature even though I do not work in this or any scientific field.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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