2011 Northern Hemisphere: Snow Coverage Part 1


The back and forth in the global warming debate about snow coverage is always amusing.  The debate has stated both that snow will  increase or decrease because of global warming.  Both news stories get coverage almost simultaneously because every year there are some places that get more snow than average, while others get less than average.  All a person needs to do is Google global warming, snow and let the conflicting stories and news articles paint the funny picture.

What I always do is simply show the data and my analysis of the data.  The source for the data is the Rutgers Snow Lab.  I focus on the data that is available from 1972 which means that 40 years of records will be available at the end of this year.  Of course that is only a blink of an eye on the geological scale, but that is what is available.  Here is what the weekly data shows for 2011.

The Inconvenient Skeptic

(Brown) 2011, (Blue) average, (Green) 2010: NH Snow Extent

Certainly the average trend for the year was followed as one would expect.  The late-spring to mid-summer region was lower than average, but the snow coverage rebounded on time and even faster than average for the NH as a whole.  There were regions that had less than average, but that was more than made up for in the regions that had excess snow.

This can be seen in the November 2011 “departure” graphic of the NH.

The Inconvenient Skeptic

(Blues) Extra snow, (Reds) Less Snow (White) No deviation from normal.

This really highlights one problem that people have understanding the Earth’s climate.  I was in an area that experienced more snow in the Spring, but less in the Fall.  Perceptions are formed by what people experience, unless they look at the data.  In the global sense the year was normal, but many regions experienced unusual snow coverage, that is also normal.

The average snow coverage for a year in the NH is 24.9 million km2 of snow.  2011 was almost normal at 24.7 million km2 of snow.  So while it was slightly below average, it was only -0.24 standard deviations from average which means it was statistically normal.

The Inconvenient Skeptic

(Blue) Average Yearly NH Snow coverage, (Black) average, (Shaded) +/- 2 Sigma

A linear regression would show a slight downward trend in the snow coverage, but that doesn’t have a lot of meaning.  I will get more into that in the next article on the snow coverage later this week, but for now I will leave you with the weekly snow coverage for the past 39 years.

The Inconvenient Skeptic

Weekly snow extent for the past 39 years.

This is far more valuable than the yearly average and I will break it down into more detail in the next article.  One thing it does show is that there is no reason to believe that winter snow is going to stop any time soon as the NH is still getting >45 million km2 of snow coverage each year.  That is a lot of snow.

Posted in Snow / Snowpack by inconvenientskeptic on January 30th, 2012 at 5:23 am.

6 comments

This post has 6 comments

  1. Richard Jan 30th 2012

    “but the snow coverage rebounded on time and even faster than average for the NH as a whole”.

    This was true for the sea ice in the Arctic as well. The rate of rise this year was spectacular and for a while looked like it might even reach ‘normal’ (i.e. 2+-SD) for a time – until a bubble of warmth came and sat north of Norway. It will be interesting to see how long that bubble lasts.

  2. Sheri Feb 4th 2012

    Where I live, there has been a significant increase in winter temperatures and far less snow than in the past. I know it’s warmer because we no longer need engine block heaters to make sure the cars will start. As for the lack of snow, when the roads stay open all the time and they only plow our subdivision road once or twice a year. it’s noticeable. I moved to this location in 1982. There were 10 foot drifts of snow and -20 degree temps for months. By around 2000, that ended and winters became very mild. Mountain snow came back and there are increasing snow amounts in other areas of the state, but not this specific area. I guess that makes it an anamoly? Truthfully, I want the snow and cold back!
    I do realize that we tend to remember things differently than the facts show. Is there a good source for historical weather data that provides raw data, not averages?

  3. inconvenientskeptic Feb 6th 2012

    Sheri,
    It depends on the type of data you want to see. There are many sources that have specific data, but certainly the level of detail available for the past decade is far different than for all times before.

  4. Sheri Feb 6th 2012

    I am searching for basically daily or weekly records for temperture for the last 40 years for Wyoming. Usually, I find only compilations of the data: averages, etc. I’m not sure if the raw data is out there since data tends to be presented already processed.

  5. inconvenientskeptic Feb 6th 2012

    Sheri,

    The Weather Underground:

    http://www.wunderground.com/history/airport/KCYS/2012/2/6/MonthlyHistory.html

    is useful for pulling daily data back pretty far. Using the above link I can see daily temp data as far back as the 1960’s. Not all locations will have that range, but if you look around, you can probably find a place nearby that does.

    It does take some practice, but once you get used to it, it is fairly simple.

  6. Sheri Feb 6th 2012

    Yes! That is precisely what I needed. Thank you.

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