Comments 1 to 11:

1. Roger A. Wehage at 20:36 PM on 20 October, 2010
   I believe that here is an excellent example of what John is describing related to temperature effects on snowfall. Below is a plot of the annual snowfall in Houghton, Michigan listed in tabular form on the above website.

   From Climate Change

   Houghton's snowfall is primarily influenced by moisture from the lake (lake-effect snow) and temperature. The graph clearly shows three trends, a relatively constant annual snowfall from 1890 to around 1935, an increasing annual snowfall from around 1935 to around 1980, and decreasing annual snowfall from around 1980 to 2010. I don't have access to average annual winter temperatures, but it is likely that average winter temperatures were colder between 1890 through the 1930s and have been rising steadily until today. Assuming the above, then during the colder years from 1890 to the 1930s the lake likely froze over earlier and thawed later, allowing less moisture to evaporate into the air and reducing lake-effect snow. From the 1930s to around 1980, as winter temperatures increased, the lake started to freeze over later and thaw earlier, allowing more moisture to evaporate, which increased lake-effect snowfall. After around 1980, as temperatures continued to rise, more of the moisture was likely falling as rain, so the average annual snowfall started decreasing again.
2. Roger A. Wehage at 22:08 PM on 20 October, 2010
   Below is a scatter plot of the monthly snowfall in Houghton, Michigan by year prior to 2010 as given here.

   From Climate Change

   The data shows a relatively uniform amount of snowfall in the months of October and November across the 120 year span. In these months the lake would generally be warmer and not frozen over, so evaporative moisture would be available, but temperatures more likely to be too warm for snow. Then in December, January, and February the monthly snowfall steadily increases as the years get closer to 2010, but only up to a point. These would be the months of colder temperatures and partially to fully frozen lake surface. As John pointed out, less snow tends to fall in extremely cold temperatures, and in this case, less snow also falls when the lake is frozen over. So in the far out years both extremely cold temperatures and frozen lake were likely to have occurred more often. In intermediate years of higher snowfall, the temperatures started to moderate and the lake froze over later, allowing more evaporation and more opportunity for substantial snowfalls. Then the plot shows significant declines in monthly snowfall in these months from around 1980 to present. Most significant are the months of January and February. My guess for this is that the lake had little ice in December, allowing more evaporation, and the temperatures were periodically cold enough to allow substantial snow and other times rain. Then the lake partially froze over in January and February, reducing the evaporation rate, and the temperatures were sometimes ideal for snow and at other times for rain. The trends for March and April snowfall are less clear over the 120 year span. However, both months do appear to have a peak around the 1980 timeframe where the total annual snowfall peaked. These snowfalls were probably less associated with lake effect than with ideal snow conditions. In those years when the lake had significant ice, melting probably didn't start until May.
3. Daniel Bailey at 01:22 AM on 21 October, 2010
   Re: Roger A. Wehage (1,2) While I appreciate you using an example so near to my hometown (Marquette), I would be cautious in extrapolating local conditions from an area of complex weather patterns to the globe as a whole. Given the proximity of the Great Lakes to the Northern Jet Stream and the Arctic in general, weather here is highly variable. Even in conditions optimal for snow, if the wind direction is slightly out of alignment for any length of time, the big snow cannon in the lake doesn't hit full output. When winds are more stable, it is common to receive 4-8" of snow overnight...for many consecutive nights. The big dumps, however, come from system-generated snowfalls, not lake-effect. An "Alberta Clipper" dipping down out of the Canadian plains brings with it compressed isobars due to the deep low at the core. The high winds and energy sheer drives blizzards of 1-2 day duration, along with 18-24" snowfalls. The other source, more common now than when I was a boy in the '60s &'70s, is pressure systems moving up from the Gulf of Mexico. The enormous moisture levels they import, coupled with the colder air masses at surface levels and the tight rotation of the lows, results also in 18'24" snowfalls. The difference between them being the moisture contents of the snow they bring. Gulf-originating snowfalls tend to have moisture contents nearly double that of the Alberta Clippers. And as snowfall accumulations here are a function of moisture contents, total precipitation may be a better comparator for weather patterns here pre-1980 and post 1980. But thanks for the trip down memory lane. By the way, the record snowfalls up in the Copper Country (where Houghton is located) is 355" in the winter of 1978-1979. Marquette received over 320" the winter of 2001-2002. PS: Snow melts throughout the winter (through various warm spells), but spring onset happens well before May. This year, March had no snowfall recorded here and temps were in the 40s. Apart from a brief 2-day snowfall in early April, spring came in March this year, with April hitting 80s and May, 90s. Too hot. The Yooper
4. Roger A. Wehage at 03:35 AM on 21 October, 2010
   Re: Daniel Bailey @3: I didn't claim that lake effect was the only contributing factor to the large snowfalls in the Upper Peninsula. But it is likely the most significant factor. If it were not, then one might expect similar snowfalls over northern Minnesota, northern Wisconsin, the Upper Peninsula, and parts of Canada to the west and northwest of Houghton. For example, the most snow to fall in a season anywhere in Minnesota was 170 inches, far short of Houghton and Calumet. One could look at current and historical weather radar data to see the origin and extent of rain and snowfall in particular areas. Typically one often sees precipitation originating and falling over the water and moving inland. Another factor is that warm, moist air over lake waters likely moderates temperatures downwind and increases the amount of snow associated with Alberta Clippers. And I agree with your comment about heavy snows from the southwest, which shouldn't be affected by lake moisture. Minneapolis has experienced a number of heavier snowfalls over the past 40-50 years, and it is likely that more of the moisture comes up from the southwest.
5. dvaytw at 18:35 PM on 20 April, 2013

   Deniers I've argued with about this claim that this is a "post prediction" in that scientists were earlier saying we should expect warmer and drier witners.  Can someone provide me articles dis-proving this claim?

6. scaddenp at 07:22 AM on 21 April, 2013

   dvaytw - in very general terms, the Clausius–Clapeyron relationship between temperature and water vapour is known from mid-19th C. Issues with precipitation were flagged in Ch 4 of WGII of the IPCC FAR 1990. Beyond the broad picture however, regional climate prediction was not possible then (and remains a considerable challenge now  -see for instance here) and so perhaps you ask the source of the their claim for drier winters? 

7. michael sweet at 23:27 PM on 16 January, 2019

   Molsen,

   This copy of the graph Daniel Bailey posted on another thread yesterday shows that spring snow extent has decreased for decades.  Your "dozen years" includes the lowest ever measured snow extent.  It is clearly a blatant cherry pick starting after snow extent collapsed.

   

   The Rutgers snow lab also has winter and fall graphs"

   

   fall:

   

   I see little winter change while fall is increasing.  It appears that the additional atmospheric water is causing increasing snowfall when it is cold in spite of the fact that temperatures have increased.

   According to this peer reviewed article (written by a Rutgers scientist):

   "Annual snowfall is projected to decrease across much of the Northern Hemisphere during the twenty-first century, with increases projected at higher latitudes. On a seasonal basis, the transition zone between negative and positive snowfall trends corresponds approximately to the −10°C isotherm of the late twentieth-century mean surface air temperature, such that positive trends prevail in winter over large regions of Eurasia and North America. Redistributions of snowfall throughout the entire snow season are projected to occur—even in locations where there is little change in annual snowfall. Changes in the fraction of precipitation falling as snow contribute to decreases in snowfall across most Northern Hemisphere regions, while changes in total precipitation typically contribute to increases in snowfall."

   It appears that the observed changes in snowfall are what scientists expected in advance.

   I find it striking that two different new posters mention snow extent.  Did WUWT have a snow article this week?

8. JoeT at 06:29 AM on 23 December, 2022

   It is commonplace that when winter arrives and heavy snowfall occurs that someone, somewhere will trot out the alleged quote in 2000 from David Viner, formerly of the University of East Anglia that 'within a few years winter snowfall will become "a very rare and exciting event".' Supposedly he also said, 'Children just aren't going to know what snow is'. 

   I searched this site and was unable to verify whether the quote is accurate. Specifically, whether he actually said 'in a few years' back in 2000. I couldn't find anything from Viner himself as to whether he was quoted accurately. It's not that this quote has any relevance to climate science in general — we all make comments that we wish we hadn't made. But I did want to know whether the quote is accurate for that moment when someone will bring it up in the local press. Thanks in advance!

    

9. MA Rodger at 08:07 AM on 23 December, 2022

   JoeT @8,

   Most internet references to the Viner comment appear to cite an article in the Independent of 20/3/00 but the links to this article yield "page not found". But for the curious, a PDF of the article has been preserved by the denialists on the rogue planetoid Wattsupia. Note the later Viner quotes in the artiucle.

   "Heavy snow will return occasionally, says Dr Viner, but when it does we will be unprepared. "We're really going to get caught out. Snow will probably cause chaos in 20 years time," he said."

10. One Planet Only Forever at 08:21 AM on 23 December, 2022

    Joe T @8,

    I share your interest and curiosity regarding those quotes by David Viner in 2000.

    My admittedly amateur search on the Internet of Knowledge (and a massive amount of nonsense), found the earliest mentions to be in 2010 by climate denying people presenting their 'interpretations (potentially misunderstandings) of the quotes'.

    It does not appear that any of them asked for clarification from the person they quote. That, along with the 10 year delay in making claims about the quotes, is a Red Flag to me. There appears to be no mention of David Viner's updated thoughts on the matter (I have read about the many incorrect statements made by Einstein that he later corrected).

    The response by Tamino dated March 5, 2011 (here) appears to be a sensible evaluation of the merits of claiming that Viner's comments in 2000 are proof that climate scientists make incorrect statements. In this case the evidence appears to indicate that Viner was correct to say what he said in 2000. Mind you, if he had made an incorrect statement he later corrected it would also be incorrect to bring up the previous incorrect statement as evidence that 'in general' climate scientists 'are incorrect'.

11. MA Rodger at 04:11 AM on 24 December, 2022

    On this David Viner quote from 2000 discussed @8,9&10, I think it's fair to say it applies to Southern England and is saying snow (perhaps lying snow rather tha snowfall) will be a lot rarer in coming years.
    The Met Office does produce UK maps of both 'snow days' and 'snow lying days' for 30-year periods. These show decline in both with the more dramatic decline in 'snow days' although the most recent version of these maps (1991-2020) are yet to be published. (See maps in Fig 1 in this CEH 'Snow in Britain: the historical picture and future projections' document from 2016).
    Of course, all these maps are saying is that the 1990s were less snowy than the 1960s and the 2000s less snowy than the 1970s.

    There is a better reckoning showing to winter 2012/3 in this 2013 Reading Uni blog which shows graphs of the annual number of 'snow lying days' at Reading since 1948/9. This shows the decline in snowiness up 2008 was reversed in the following years.

    Another less-exacting attempt to show the level of UK snow is graphed out by decade below, based on this record here. Taking the method up-to-date puts the latest ten-years (2011/12-to 2020/21) at 22, so the snowiness is again showing decline, although a couple of 'very snowy' years would soon boost that up again.

    

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