September 26, 2021

Heat Wave Versus Cold Wave Deaths in The U.S. and the Pacific Northwest

There have been a lot of stories about heatwave deaths this summer and the latest Washington State Department of Health (DOH) statistics indicate that the June 2021 heatwave contributed to 91 deaths.   

The DOH also noted that 39 individuals died from heat-related complications from 2015-2020.  Nearly all of those who lost their lives were either elderly or suffered from serious pre-existing conditions.

Heatwave deaths are all tragic losses and we should do all we can to prevent them, including expanded use of air conditioning, cooling centers, and more.

But it is also important to understand the other "side of the coin", about deaths resulting from cold waves, both in the Northwest and the rest of the nation.

And the facts may surprise you.  Far more people die from cold than heat.  

Furthermore, cold waves sometimes kill young people, often on icy roads.

Consider the national statistics provided by the U.S. Environmental Prediction Agency.  Based on hospital records, the death rate of coldwaves (top) is at least TWICE that of heatwaves (bottom)



A 2014 study by the U.S. Department of Health and Human Services found that from 2006–2010 about 2,000 U.S. residents died each year from weather-related causes  About 31% of these deaths were attributed to exposure to excessive natural heat, heatstroke, sunstroke, or all; 63% were attributed to exposure to excessive natural cold, hypothermia, or both.  

Cold was twice the threat of heat, consistent with the findings of the EPA.

And an article in the well-known medical journal, The Lancet (Gasparinni et al. 2015), took a more international perspective examining data from 384 locations in Australia, Brazil, Canada, China, Italy, Japan, South Korea, Spain, Sweden, Taiwan, Thailand, UK, and the U.S. found that cold was MUCH more of a ratio of roughly 15 to 1.

Imagine courtesy of the Lance.

I could provide more publications, but the message is clear and consistent: 

Coldwaves kill many more people than heatwaves.  

The recent Texas cold wave provides a stark example, with at least 210 losing their lives.  And here in Washington exposure under cold conditions frequently kill the homeless and even folks inside unheated homes.  I found several dozen of such deaths in the Northwest media during the past ten years alone.  And there is a proven relationship of cold contributing to cardiac deaths in our area (see here for one study)

It is clear that the threat of cold is vastly underplayed by these statistics.  Cold waves are associated with icy roadways and ice on roads is a major cause of accidents, particularly in our state.

A few years ago I checked the WA State Patrol database, finding that one to two dozen WA citizens lost their lives each year through accidents on icy roads, with hundreds being injured.  Washington DOT statistics were consistent with this.

As a young professor, I started doing forensic meteorology research, and the number one reason lawyers called me was to aid in cases with deaths on icy roads.  And for those interested in social justice issues, such icy deaths fell predominantly on more vulnerable groups, who often traveled in the early morning hours to agricultural, construction, or service jobs.

Icy road accidents, often associated with western WA snow events, often hurt the young and healthy.

Global Warming Implications

Now let me say something that is true, but unfortunately will get some folks upset.  

Since cold waves kill more people than heatwaves, global warming might well cause fewer deaths overall.  Ok, I said it.  And it is true, unfortunately, that the media, such as the Seattle Times and National Public Radio (e.g., KNKX) never mention this fact.    Heatwaves are discussed endlessly, but the harm of cold waves is ignored.  And you know why.

This is NOT to say we should ignore global warming because warming might save lives and lessen injury.   We should take prudent and economically reasonable steps to minimize warming because of other issues.  That is why I support a carbon tax, nuclear power, and the realistic use of renewables.  And we need to ensure we talk prudent adaptation steps.

But let us at least acknowledge the truth of temperature extremes and human harm.


The Second Edition of My Northwest Weather Book is Now Available!

Finally, the supply chain issues have been overcome.  My new book is immensely improved over the first edition, with new chapters on the meteorology of Northwest wildfires and the weather of British Columbia.  A completely revamped chapter on the effects of global warming on our region.  And it has been brought up to date with recent weather events and the imagery is improved greatly.

Where can you get it?

Local bookstores, such as the University of Washington bookstore.  The UW Bookstore has just received several dozen copies.

Or Third Place Books in Lake Forest Park or Seattle.

And yes, there are online sellers like Amazon, which I understand ordered over 2000 copies.


  1. Cool spinning hurricane eye type low off shore. Is that gonna produce wind?

  2. Many years ago wife drove about 25 miles to teach in a rural school district. This meant a longish drive on marginal two lane highway before it started warming up. It was with great relief when the state and schools allowed a 2 hour late start when roads were icy or snowy and still considering it a full day. School bus drivers and parents were also greatly relieved.

  3. Your statistical evidence is valid and adequate to compare the immediate and direct effects of hot and cold waves on humans. However, you're ignoring the secondary hazards and harms, and the environmental impacts. Hot spells, especially at high latitudes, tends to feed other amplifying mechanisms like sea ice loss, melting permafrost and methane releases. I know of no comparably powerful amplifiers that are triggered by colder weather. There's the albedo effect, but it's not as potent, is it? Here in Colorado, trees are suffering for the lack of cold winter nights. It takes a week of 20 below lows to kill the mountain pine beetle, and that doesn't occur anymore. And speaking of human impacts, hot weather has been correlated with aggressiveness.

    We don't get a choice of warmer or colder climates, of course. We're getting both, alternating in greater intensity. Speaking of the whole country, not just the relatively placid land of Pugetopia.

    1. There is a lot more. Increasing CO2 enhances plant productivity, which is good for agriculture and forest growth and cold waves can have enormous costs (e.g., Texas). But global warming has clear negatives as well (e.g., rising sea level). My point here is that these are complex issues and not as straightforward as some suggest.

    2. "We don't get a choice of warmer or colder climates, of course. We're getting both, alternating in greater intensity."


      That's simply false. The eco types have to make up lies because the facts are against you.

  4. Cliff, you are skirting Strawman territory. Might as well argue that there will be fewer medical emergencies associated with shoveling heavy snow, winter weather related car accidents or slips on ice with a warming climate. Yes, your point is contrasting two sets of data to further discredit the MSM, but it also comes across as possibly being interpreted as "Hey, this global warming thing might not be so bad".

    The real question is will be be a net gain or loss. Yes, less slips and falls but more deaths from malaria and other tropical diseases might not pencil out favorably.

    Plus, the example you cite about Texas is baloney. Those people died because their POWER WAS OUT due to disruption in thermal fuels for power plants. How would our heatwave here in June have played out if the entire region lost power? Its 108 degrees and you can't even power a FAN. Yah, lots are going to die, Cliff. Its not a fair comparison.

    Most of the world's current regional conflict zones also have much in common: Brutally hot weather. Plus when its really hot, productivity suffers. Some areas will probably strongly benefit by a warmer world. Disasters tend to reshuffle the winners and losers, thus Canada could make out like a bandit. Perhaps Siberian Russia. The locals where its already brutally hot? It doesn't take a PhD to deduce that those areas are SCREWED. Still, they could become a non-statistic by virtue of being uninhabitable. A future statistic could extoll this virtue: No one died in the much hotter Middle East...because no one lives there now.

    1. Speaking of baloney, let's chat about your outrageously dishonest characterization of Cliff's post, which mentioned Texas along with numerous worldwide data collections. Anyone who reads your post and Cliff's knows where the baloney is. My question: Why do eco-warriors lie about facts?

    2. Fine. Lets chat. A fair comparison of Texas last winter and the Puget Sound when it hit 100+ for 3 days is only FAIR if the benefit of ELECTRICITY is removed for BOTH situations. Texas doesn't do cold well and we don't do hot well. Texas had the death toll due to a double whammy of relatively extreme cold as well as NO POWER for a broad spectrum of the population in Texas. If you want to defend Cliff from a conservative standpoint in refute of what climate change may represent, than have at it. Just make sure you have your context right. If the Puget Sound did not have the benefit of power, this discussion in MY OPINION would not be relevant based upon the examples provided. I am not on THEIR side or YOU'RE side. I'm on MY SIDE. If something is BS, I am gonna call it.

    3. Malaria is spread by mosquitoes, which can be killed, and its rate is a function of (a) health care; (b) heat; and (c) humidity, it seems. Malaria deaths have been cut by some 40% in Africa in recent years, even while AGW increases, due to treatment and nets. There is no reason this trend should not continue.

      Heating has been greatest around the poles. Some parts of the ME have heated moderately, but use of air conditioners has increased exponentially, as have the population of ME countries. The assumption that all this is going to change in the next 50 years, seems quite unwarranted. The spread of air conditioning has made previously uncomfortable climates much more livable. Of course global warming is an important concern, and carefully-considered actions need to be taken, but Cliff is right, all facts must be faced, even if only to make convincing propaganda.

    4. *shrug* Its probably likely that most are "concerned", but the reality is nothing will stop it, and we just have to figure out how to live with it at its relative worst indefinitely. Apply that to any large, abstract problem facing Humanity.

  5. Correct me if I am getting the wrong impression Cliff- for some reason you are a lot more concerned by media coverage of global warming than the phenomena itself.
    Just basing this observation on your postings.
    It seems like a mission for you to address media, rather than to address the issue itself.

    1. That is incorrect. The only way to effectively deal with climate change is for society to have accurate information about the topic. Poor information and miscommunication about climate change by the media is a profound problem that will cripple our ability to deal with climate change. That is why it is important to deal with it. A good example is blaming forest fires on climate change and neglecting thinning and restoring forest ecology.

    2. So Cliff Mass Blog addresses inaccurate information about climate change from a variety of media sources that both overstate and understate or deny the reality and threats of human caused climate change? This should be a testable hypothesis.

    3. Thank you for your reply Cliff.
      We in the NW (west of the Cascades)are lucky, being much less vulnerable to drought, heat, and/or flood than most other regions of the world.
      Expect a progressive wave of climate refugees into the region over the next few decades.

  6. This post is going to age like milk when we start seeing parts of the world pass the wet bulb temperature for human survivability.

    1. I can not agree. The projections you are talking about are based on unrealistic (RCP8.5) simulations. More realistic simulations show little areas or times reaching the wet bulb limit you are talking about (about 95F).

  7. I know this was posted yesterday (Sunday) and it's now Monday morning but just wanted to mention another aspect of the cold, and that is many young people (and I put it loosely as anyone younger than 50 seems to think just because it's cooler, it's still OK to not wear a jacket, or wear a pair of shorts, or a short sleeved T-Shirt, sans jacket and be OK, when your extremities (arms and lets) are more prone to heat loss (as well as one's head) than your main body.

    Below 55, I get cold, just looking at people dressed this way as I wear the appropriate clothing when it gets 55 or below.

    One aspect that we get here, and may be the case elsewhere is the rain and colder temps (45-55 or so) is the dampness that comes from the rain that can seep into one's bones and can cause one to shiver or feel cold. Sometimes I'm more prone to this than other days is something to factor in when it comes to the higher deaths from when it's cold out. It's not the answer, but one of many factors.

    I like to think of it as the invincible factor, I'm young, I can "handle it" and not think about the negative effects of such a thinking.

    1. Seattle doesn't really get all that cold compared to most places, and especially compared to other places where exceeding 85F is a rarity.

      As a dedicated four season shorts wearer around here, I remind you that people have differing tolerances for both heat and cold. My perfect high/low temperatures are 65/45. My friend who grew up in Hawaii throws on layers below 65. Neither of us are right or wrong -- we just have different bodies and different preferences.

      I've always run hotter than most people. 25 years ago, I was a teenager who was crossing a frozen river in -15F weather. The ice at the river bank had contracted away from shore due to the profound cold, but that also made it thin. It gave way when I stepped, and I found myself immersed up to my knees with miles to go to my car. I was frightened but didn't panic, setting out immediately and refusing to stop until I made it. My pants froze into insulating blocks, while hot blood coursing down my legs kept the water liquid against my skin until I could reach my car and strip those layers off. I believe that my experience could have ended tragically for a person less adapted to bitter cold than I was.

  8. You are making the assumption that there is no linkage between global warming and cold waves. While there has been a lot of junk information coming out of the media (and some academics) on this subject, last month there was a paper published in Science by scientist at MIT, UMass, and Hebrew U that does show a link using rigorous scientific analysis: Linking Arctic variability and change with extreme winter weather in the United States by Cohen, Agel, Barlow, Garfinkle, and White.

    1. Too cold? Global warming.

      Too dry? Global warming.

      Too wet? Global warming.

      Too hot? Global warming.

      Just right? Global warming.

  9. Our ability to adapt to climatic changes is the main reason that humans have become the dominant species on this planet. It seems that we are losing that ability as time passes.

    I've always found it easier to stay warm that to stay cool. I can always layer up or pile on more blankets to stay warm. There's only so much I can do to stay comfortable as the temp rises.

    The problem of more people being killed in car crashes on icy roads is simply a case of not being prepared for the conditions. A properly equipped vehicle driven by someone with training and/or experience can easily get from point a to point b without issue.

  10. I grew up in Las Vegas, which has months of triple digit temperatures. The best way for me to cool down if I get overheated is to take a cool to lukewarm shower. I did that during this summer heat wave and it was very effective.

    A friend of mine who grew up in Yakima jumps in a lukewarm bath when it gets too hot. She gets an ice tea and a good book and spends the hottest part of the day relaxing.

  11. Another thing I never see brought up regarding the AGW debate - on average, it takes less energy to cool your place down to acceptable levels compared to comparable heating. Granted, the extremes of the SW and the deep South may mitigate this factor somewhat, but when you measure the BTU 's from cooling to heating the temparature differences are usually less dramatic. When I lived in the Midwest, it cost far less to cool my place down from 90 degrees to 76 degrees compared to heating my place from 20 degrees to 64.

  12. If you plot a trendline for both hot and cold weather related deaths, the cold weather appears to be increasing in deaths.

    With climate change, could colder winter weather occur more frequently in western Washington? Regardless of whether that is the case, do you think we should make more investments in cold weather infrastructure upgrades?

  13. Misses the point, which is that more people are dying of excessive heat-related complications where it was not a traditional concern. Prolonged exposure even to mild temperatures can become deadly, so naturally, those numbers are going to be more significant.

    People dying from excessive heat while sitting within their own homes isn’t even a comparable factor to deaths due to having to venture out on a predictably icy road during a 25-degree winter day.

    1. Icy roads are far less predictable than heat waves (which are very well predicted) I can't follow your logic here.

    2. I think the logic is that crashing a car on an icy road is rooted in a behavioral choice and involves human error, whereas just living in a hot house and dying from the heat is more comparable to deaths from exposure to the cold.

    3. Unknown...this does not make sense. Crashing on an icy road going to work is NOT a behavioral choice. People have to work, go to school, etc.

  14. Maybe correlate that cold weather death trendline with the trendline that reflects the rise in homelessness?

    Look, it can be bitter cold or broiling hot but if you have inadequate resources to mitigate either you end up just as dead. The wealthy and the strong will be fine. Darwin had this figured out for us.

    Climate change is really a further examination of our species' relationship with the more vulnerable and disadvantaged in our ranks. We have to decide if "Surplus Population", as per Covid, is a sacrifice for the greater good or something to preserve for the overall commonwealth. THAT really is the issue if we are going to get into the statics of death due to weather events.

    In nature, the old, the sick and the weak die when inherent variability in the ecosystem greatly limits the resources available to sustain a given population. Science has extensive, well documented examples of how Nature is brutal in its calculus of who lives and who dies. Supposedly, we Humans are better than that...but are we? Science can be cruel in its analysis and conclusions in many ways. Part of that is that we live on the same Earth and follow the same rules as every other life form. Adapt, evolve or die out.

    Best suggestion is to get educated and have plans in place. This is the USA. Best to assume that if you fail its on YOU. Texas made it perfectly clear that when those people died in the cold snap/power failure, it was THEIR FAULT for not being prepared as well as thinking they could rely on government or industry to look out for them. I am not condoning the very American practice of victim blaming. Still, our country does NOT have a tradition of civic activism or working for the collective good. These are the parameters. Ultimately, combating climate change is an individual decision.

    1. Oh please! The imbalance between deaths from cold vs. from heat is a WORLD phenomenon, as Cliff's post documents. No amount of your self righteous dishonesty changes that. You can share your illogic and denial of facts with your fellow propagandists, but the FACTS are against you.

  15. Where does the last 20,000 years of global warming to melt that 5000' ice sheet that used to sit on top of your office fit into the man-made global warming scheme, and the 20 year solar cycles that appear to affect earth temperatures and climate significantly more than anything else? Asking for a fren. - E

  16. Something doesn't add up here. If heat waves and cold waves factor in 94% of weather related deaths, that leaves just 6% for deaths due to coastal storm surges, windstorms including tornadoes, floods, lightening caused fires, etc.

  17. You should probably include the deaths from BC and Oregon in your counts. BC had 596 deaths due to the June heat wave. I strongly suspect there has not been a similar cold wave toll in BC.
    Also the graphs you presented from the EPA are deaths from heat and cold. They are not plots of deaths from cold waves or heat waves. The same EPA site and reports state that heat related deaths were very likely to increase more than the very likely decrease in cold related deaths.

    1. It would be interesting to check Canadian cold death stats. I expect the further north one goes, the fewer fatalities from cold waves...folks are prepared. I don't think there is any study showing how the number of cold wave deaths change versus heat waves in the future. But we know that cold waves kill FAR more people now than heat waves and cold waves will DECLINE as the earth warms.

  18. Climate activists are now using an endless barrage of climate science arguments as a means of avoiding an honest and comprehensive debate concerning what specific actions must be taken if we are to quickly reduce our carbon emissions.

    The criticisms against Cliff Mass here on this blog, and elsewhere against other competent scientists holding contrarian views about the actual long term dangers of climate change, are examples of this tendency.

    These activists refuse to acknowledge that President Biden already has all the legal authority needed to unilaterally impose a fossil fuel lockdown on the American economy.

    As a demonstration of just how far Biden could go legally in guaranteeing that his ambitious GHG reduction targets can be met, I've created the Supply Side Carbon Emission Control Plan (SSCECP). Here is a general overview of the plan:

    -- Declare a Climate Emergency under the president's national security authorities. Declare a Carbon Pollution Emergency under his Clean Air Act authorities. Publish a Climate Crisis Response Plan (CCRP) which coordinates the individual actions to be taken under both sets of legal authorities.

    -- Subsume all current GHG reduction plans, initiatives, and agreements at all levels of government and place them under direct federal authority. Issue a series of Executive Orders which further define and enable the implementing actions to be taken under the SSCECP.

    -- Establish a system of carbon pollution fines which is the functional equivalent of a legislated tax on carbon. Establish production control agreements with fossil energy corporations which guarantee similar or higher profit margins on declining levels of production and distribution.

    —- On a case by case basis, suspend or bypass specific portions of the National Environmental Policy Act (NEPA) along with portions of other project permitting requirements if such action is deemed to be 'in the national interest' as that term is defined within the Climate Crisis Response Plan (CCRP).

    -- On a case by case basis, reverse any specific regulatory or energy facility permitting decision made at any level of government if that decision is determined to be 'not in the national interest' as that term is defined within the Climate Crisis Response Plan (CCRP).

    -- On a case by case basis, assert federal eminent domain over those lands, waters, and properties, either publicly owned or privately owned, which are to be reserved wind, solar, nuclear, energy storage, and/or power transmission development.

    -- Establish a hard target schedule for the phased shutdown of America’s fossil energy production facilities and their associated support infrastructure.

    What could Governor Jay Inslee and the Washington State Legislature do under their own legal authorities to quickly reduce the state's direct and indirect contribution to the world's total carbon emissions?

    -- Impose significantly higher taxes on all forms of carbon energy. Place increasing restrictions on the sale of ICE vehicles, both new and used.

    -- Impose a phased reduction in the number of jet airliners allowed to use the state's major airports.

    -- Target Boeing with higher taxes and with stricter environmental compliance and work place safety rules if the corporation refuses to commit to producing a non-polluting airliner by some specific date.

    -- Force the closure of the state's six petroleum refineries by imposing stricter environmental compliance and work place safety rules which cannot be economically met.

    President Biden, Governor Inslee, and the Washington State Legislature all have a clear mandate from the voters to pursue aggressive action on climate change. Will they, or won't they, take all the action they are legally empowered to take?

  19. I think you gave an incomplete accounting of the results from the cited Lancet (Gasparinni et al. 2015) paper. It makes clear that the impact of temperature on mortality is highly non-linear, with a far more rapid increase as temperatures exceed the minimum mortality temperature (MMT) than as when temperatures dip bellow. As a result, a few degree increase in the temperature of a day warmer than MMT will generally cause a far greater increase in mortality than the decreased mortality which results from increasing a the temperature of a day cooler than MMT. Therefore, despite nearly all locations having significantly more time bellow MMT than above (an hence cool weather contributing more to total mortality), one can not simply state that increasing the average temperature will decrease total mortality, as mortality appears to be far more sensitive to changes above MMT.

    To make actual predictions on changes in mortality rate, one would have to use the expected temperature histograms resultant from global warming in conjunction with the paper's calculated relative-mortality-risk as a function of temperature to calculate the new expected total mortality.

    It just so happens that there is a 2020 working paper from the National Bureau of Economic Research ("Valuing the Global Mortality Consequences of Climate Change Accounting for Adaptation Costs and Benefits", Carleton et al.) which has done just that. They estimate that with adaptation and income growth the average annual mortality increase per 100,000 will be 11 under RCP4.5 and 73 (comparable to all infectious diseases) under RCP8.5. I suppose it is notable that there analysis did not include more optimistic emission scenarios, but based on the work it seems reasonable to expect global warming to increase total mortality.

    1. AlexH... I don't think you are correct. We know that there have been many more cold wave deaths than heat wave deaths. This is definitive. And since global warming is slow, there will be true for a while. Cold deaths extend over a much larger temperature range than heat deaths....and a projection of the frequency of cold anomalies projects more strongly than warm anomalies on to it. It is true that there is a rapid rise of deaths for extreme heat, but those are infrequent today and the studies you are discussing make use of unrealistic warming scenarios for the end of the century (eg., RCP 8.5). The bottom line is that cold wave deaths are dominant today and minor warming will still result in the dominance of cold wave deaths, which should decline as the earth heats up during the next decades.

    2. You continue to oversimplify the necessary analysis to reach your conclusion. Just because more people die from cool weather than warm weather, it does not naturally follow that warming will decrease deaths. The question is whether deaths attributable to warm weather will increase more or less than deaths attributable to cold weather. The 2020 NBER paper I cited attempts to do just this, and find an increase in temperature related deaths for both RCP 4.5 and RCP 8.5. Where do you disagree with there analysis? Do you consider RCP 4.5 to be unrealistic? I actually found the paper to be quite measured, even attempting to factor in the potential for adaptation and the economic development of poorer countries to blunt the impacts on mortality.

  20. Cliff, congratulations on the 2nd edition of your book! Will you be doing any signings?


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

More Rain for the Northwest is Good News for Wildfires

After a very pleasant dry spell, another rainy period is ahead for the western side of the region and the Cascades on Friday and Saturday.  ...