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Higher Snowfalls Due to Change In Measurement, Not Global Warming.

January 30, 2015
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By Paul Homewood

 

 

 

We all know that snowstorms are worse than ever before, and that it is all the fault of global warming.

After all, Bill Nye himself told us!

 

Unfortunately, Matt Kelsch, a hydrometeorologist at UCAR, throws a spanner in the works. Matt specializes in weather and climate events involving water, such as floods, droughts, rain, hail, or snow, and has also spent the last 25 years taking snow measurements in Boulder, Colorado, as a volunteer for the NWS.

Matt wrote this article for UCAR News yesterday:

 

image

http://www2.ucar.edu/atmosnews/perspective/14009/snowfall-measurement-flaky-history

 

As a hydrometeorological instructor in UCAR’s COMET program and a weather observer for the National Weather Service, I am keenly interested in weather trends. In this case, climate change is an important factor to explore, since we know that the heaviest precipitation events have intensified in many parts of the world

But when we turn to snowstorms in the Northeast, or elsewhere in the U.S., there is an additional factor at work when comparing modern numbers with historical ones. Quite simply, our measuring techniques have changed, and we are not necessarily comparing apples to apples. In fact, the apparent trend toward bigger snowfalls is at least partially the result of new—and more accurate—ways of measuring snowfall totals. Climate studies carefully select a subset of stations with consistent snow records, or avoid the snowfall variable altogether

Official measurement of snowfall these days uses a flat, usually white, surface called a snowboard (which pre-dates the popular winter sport equipment of the same name). The snowboard depth measurement is done ideally every 6 hours, but not more frequently, and the snow is cleared after each measurement. At the end of the snowfall, all of the measurements are added up for the storm total.

NOAA’s cooperative climate observers and thousands of volunteers with the Community Collaborative Rain, Hail and Snow (CoCoRaHS), a nationwide observer network, are trained in this method. This practice first became standard at airports starting in the 1950s, but later at other official climate reporting sites, such as Manhattan’s Central Park, where 6-hourly measurements did not become routine until the 1990s.

Earlier in our weather history, the standard practice was to record snowfall amounts less frequently, such as every 12 or 24 hours, or even to take just one measurement of depth on the ground at the end of the storm.

You might think that one or two measurements per day should add up to pretty much the same as measurements taken every 6 hours during the storm. It’s a logical assumption, but you would be mistaken. Snow on the ground gets compacted as additional snow falls. Therefore, multiple measurements during a storm typically result in a higher total than if snowfall is derived from just one or two measurements per day.

That can make quite a significant difference. It turns out that it’s not uncommon for the snow on the ground at the end of a storm to be 15 to 20 percent less than the total that would be derived from multiple snowboard measurements.  As the cooperative climate observer for Boulder, Colorado, I examined the 15 biggest snowfalls of the last two decades, all measured at the NOAA campus in Boulder. The sum of the snowboard measurements averaged 17 percent greater than the maximum depth on the ground at the end of the storm. For a 20-inch snowfall, that would be a boost of 3.4 inches—enough to dethrone many close rivals on the top-10 snowstorm list that were not necessarily lesser storms!

Another common practice at the cooperative observing stations prior to 1950 did not involve measuring snow at all, but instead took the liquid derived from the snow and applied a 10:1 ratio (every inch of liquid equals ten inches of snow). This is no longer the official practice and has become increasingly less common since 1950. But it too introduces a potential low bias in historic snowfalls because in most parts of the country (and in the recent blizzard in the Northeast) one inch of liquid produces more than 10 inches of snow.

This means that many of the storms from the 1980s or earlier would probably appear in the record as bigger storms if the observers had used the currently accepted methodology. Now, for those of you northeasterners with aching backs from shoveling, I am not saying that your recent storm wasn’t big in places like Boston, Portland, or Long Island. But I am saying that some of the past greats—the February Blizzard of 1978, the Knickerbocker storm of January 1922, and the great Blizzard of March 1888—are probably underestimated.

So keep in mind when viewing those lists of snowy greats: the older ones are not directly comparable with those in recent decades. It’s not as bad as comparing apples to oranges, but it may be like comparing apples to crabapples.

Going forward, we can look for increasingly accurate snow totals. Researchers at NCAR and other organizations are studying new approaches for measuring snow more accurately (see related story: Snowfall, inch by inch). 

But we can’t apply those techniques to the past. For now, all we can say is that snowfall measurements taken more than about 20 or 30 years ago may be unsuitable for detecting trends – and perhaps snowfall records from the past should not be melting away quite as quickly as it appears.

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10 Comments
  1. January 30, 2015 12:35 pm

    So interesting ….. and logical.

    And if the snowboard measurements were every 3 hours, or every hour, or after every 5cm snow fall, there’d be even more chance of record-breaking events.

  2. January 30, 2015 2:22 pm

    Reblogged this on eliquidassets and commented:
    Gives an understanding on historical data to present data when measuring weather phenomena.

  3. Retired Dave permalink
    January 30, 2015 4:28 pm

    Snow is measured as a depth, but also melted to give a “rainfall” figure amount. Some snow is wetter than other snow. A rough conversion is 1 inch rain equals a foot of snow. So three feet of snow is not a very large amount of precipitation. Obviously there are inaccuracies in producing an equivalent rainfall figure (which is of course part of the annual figure)

    And of course Matt Kelsch’s snowboard has to be placed somewhere where you will measure “undrifted” snow depth – not always easy, especially when it is moving horizontally such as in a New England Nor’easter.

    All this is interesting and important –

    BUT what worries me is how climate science can tells us (10 to 15 years ago) that snow will become a rare and exciting happening – children will not know what snow is!!! and when we get shed loads of it tell us that is what they expected with global warming.

    BUT even is worse are the gullible idiots who believe them – they are like the parishioners of that American preacher a couple of years back, who when he told them that the world would end on a certain date, not only believed him: but when it didn’t end on the due date he managed to convinced them that it was just his calculations that were at fault – perhaps he divided by zero somewhere?

  4. El Sabio permalink
    January 30, 2015 7:21 pm

    Hello. Did you know that children just aren’t going to know what snow is?

    http://www.independent.co.uk/environment/snowfalls-are-now-just-a-thing-of-the-past-724017.html

  5. January 30, 2015 10:28 pm

    Reblogged this on the WeatherAction News Blog and commented:
    Yes Paul, there is even a new term for this (keep up) Anthropogenic Climate Disruption (ACD) and it is clearly evident…in snow…which we can measure with millimetre precision. The latest computer models projections have proved that whilst there is more snow now -predicted well in hindcast – it is rotten snow. It is quite possible that by 2020 the snow will be screaming as it passes through a boiling atmosphere.

    • January 30, 2015 10:35 pm

      I wish my incredulity was with just the press and fanatical extremists, but most of the effluent comes from rent seeking academia rather than the usual hyperbolic suspect of the press. Matt Kelsch is to be commended for his clarity.

      If only Gavin had the same scientific integrity.

  6. January 31, 2015 3:03 pm

    Reblogged this on Globalcooler's Weblog.

  7. January 31, 2015 10:11 pm

    Here is a recent article about this blizzard and the lake effect, with many satellte photos, which cleary demonstrate ocean supremacy: http://climate-ocean.com/2015/L.html. I also think that climate change will lead to many extreme phenomenons in the years to come.

  8. February 1, 2015 4:28 am

    Yep… Total load of shit… Claiming crazy snow due to Climate Change AFTER these same experts told us ‘snow’ would be a thing of the past…

    Basically…. Any weather event is twisted and used to promote ‘Climate Change’… Doesn’t matter if it happened before… People deny what they see with their own eyes and have no knowledge of Climate History…

    Climate Change is a HOAX…

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