{"id":291065,"date":"2023-12-13T08:07:12","date_gmt":"2023-12-13T07:07:12","guid":{"rendered":"https:\/\/climatescience.press\/?p=291065"},"modified":"2023-12-13T08:07:15","modified_gmt":"2023-12-13T07:07:15","slug":"let-it-snow","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=291065","title":{"rendered":"Let it snow!"},"content":{"rendered":"\n
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From Watts Up With That?<\/a><\/p>\n\n\n\n

Guest Essay by Kip Hansen \u2014 12 December 2023<\/p>\n\n\n

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Snow \u2013 those marvelous little crystals of frozen water that drift down from the sky \u2013 in gentle silence, in the fury of an arctic-like blizzard, or in any and everything in between.<\/p>\n\n\n\n

Where I grew up, snow was something that we traveled a couple of hours to visit<\/em> for the day.  Once a decade, we\u2019d rent a cabin up in snow- country and spend a week with aunts and uncles and cousins.  But I never had to live where it snowed in the winter \u2013 I surfed<\/em> in the winter.  Sometimes university friends and I would drive up to sled and toboggan on Saturday and drive back down to surf on Sunday. <\/p>\n\n\n\n

[This essay is only 1500 words \u2014 with a lot of graphics\u2026.]<\/p>\n\n\n\n

I saw a few weeks ago that some climate skeptic had twitted  (Xed?) that snow was not decreasing, but rather increasing.  He used little graph:<\/p>\n\n\n

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Well, fair enough, that is the Rutgers Snow Lab<\/a> graph for Fall Northern Hemisphere Snow Extent<\/strong> covering the satellite era (1967-present).  Most readers here are generally familiar with the climatic history of the last century or so, and might notice something:  during the \u201cGlobal Cooling Period\u201d  late 1960s through the mid-1970s there were years with very high fall<\/strong> snow extent, over on the left side, which are  similar to the last couple of decades, on the right.<\/p>\n\n\n\n

Note:  NOAA and NASA (for weather and climate) use:  Meteorological seasons<\/strong>:  \u201cspring \u2026 includes March, April, and May; meteorological summer includes June, July, and August; meteorological fall includes September, October, and November; and meteorological winter includes December, January, and February.\u201d<\/em><\/p>\n\n\n\n

But, this is just the fall months<\/em>: September, October, November (although Astronomical Winter<\/a><\/em> does not begin until 21 December).  And it is only the Northern Hemisphere<\/em>.  Only the Northern Hemisphere [NH hereafter] because almost all of the planet\u2019s snow, excluding the ice caps, is found in the Northern Hemisphere \u2013 there is some in the south up in the Andes of South America \u2013 but its extent is insignificant.  NASA\u2019s Earth Observatory offers this for Winter 2022:<\/p>\n\n\n

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If you look closely, you can see the little strip of white snow atop the western mountains ranges of South America. <\/p>\n\n\n\n

It is not valid <\/em>to show just the Fall NH Snow Cover Extent and then say: \u201cSee, more snow, I told ya so!\u201d. <\/p>\n\n\n\n

Total NH snow cover extent has been really very stable across the satellite period:<\/p>\n\n\n

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Both the highs and lows are pretty stable, at least since 1972  [I have some personal doubts about the two very high \u2018lows\u2019 prior to 1972 and will query Rutgers on those two data points ***].  The high extent seems to be centered on about 45,000,000 km2<\/sup>, maybe a little more.  The lowest extent somewhere between 25 and 75 million km2<\/sup>.<\/s> between 25 and 75 million km2. (h\/t Rick C)<\/p>\n\n\n\n

*** Update: from Rutgers snow Lab: \u201cYes, it was early in the satellite record! For this reason, there are some missing snow charts. They are as follows: Weeks with no data: 1968 27-30, 1969 23-43, 1971 28-39 Missing months:  July 1968, June-Oct 1969, and July-Sep 1971\u201d \u2026.. \u201cIt looks like those two data points represent May 1969 and June 1971 instead of August, which is missing during those years. I plan to add placeholders for this missing data in the text files. There is a note on the website but reformatting the data file will make the missing months more visible.\u201d \u2014 from the very helpful Tom Estilow, at Rutgers Snow Lab<\/p>\n\n\n\n

Here\u2019s another way to look at it:<\/p>\n\n\n\n

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The red and blue traces are \u201c\u2026extremes are calculated using the 56-yr record from Jan 1967 to Dec 2022 \u201c<\/strong>  so the highest for that week in the 56-year record and the lowest.  So, we can see that 2022, the black trace, was very near the highest extent in early Fall (late September) and Oct-Nov.  Otherwise, right on the mean through the Spring, and quite low late spring and through the summer. <\/p>\n\n\n\n

The point of that exercise was to show that snow cover extent  is variable, year to year, and within the same year, season-to-season \u2013 2022 from lowest in 56 years in July to highest in 56 years in November \u2013 shifting to dropping below average Dec to Jan.  That is just one year.<\/p>\n\n\n\n

Now, here\u2019s what all that is composed of during the seasons:<\/p>\n\n\n

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So, snowier Falls, a bit snowier Winters, and less snowy Springs.   The vertical scales are very close, about million Km2<\/sup> top to bottom, but each graph is a different portion of the whole vertical scale<\/em>, it is not appropriate to set them side by side.  Properly, they look like this:<\/p>\n\n\n

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So, we see that the increase in the Fall and Winter does not quite make up for the decline in the winter and<\/s> Spring.  But, looking back up at the NH Snow Extent graph up a bit  (it\u2019s blue) we\u2019ll see that there is a slight<\/em> decline since the turn of the century, but overall stable. <\/p>\n\n\n\n

With snow, Snow Cover Extent is not the same as Amount<\/u><\/em> of Snow \u2013 more commonly measured as depth  in inches (or cm or feet or meters) or as water content<\/em>.  Snow is hard to measure \u2013 obviously there is fluffy snow, grainy snow, wet snow, powder snow \u2014 many, many types of and conditions of snow \u2013 it is often said that the Inuit or the Greenlanders have \u201c40-50-200-400 \u2013 take your  pick \u2013  words for snow\u201d. [This is not strictly true, of course, but they do have a lot of words describing types of falling snow and snow conditions on the ground.]<\/p>\n\n\n\n

The U.S. National Weather Service<\/a> gives us this:<\/p>\n\n\n\n

Three Types of Measurements are Reported:<\/strong><\/p>\n\n\n\n