More on the Snow Cover in Asia

Click for larger image.

One of my near-daily stops is the National Ice Center’s snow cover web page.  Something caught my eye when I was looking at the most recent image from yesterday.  Admittedly, the image is not all that different from the one posted in the previous snow cover post.  The snow cover has advanced a little south and east in Asia, but it doesn’t seem like anything significant.  “Seem” being the key word in that sentence.

Notice the new area of snow cover near Shanghai, China about equal with the southern islands of Japan.  You’ll also notice a latitudinal line running through the southern edge of this new area of snow.  Follow that line around to the Atlantic Ocean where it is labeled.  It’s 30 degrees North latitude!  For comparison, only extreme southern Texas and the Florida peninsula are found south of 30N in the U.S.  All of Europe is located well north of this parallel.

Now, the snow cover in western China is located within mountainous regions – mainly the Himalayas.  So, this is understandable.  The eastern portion of China is not nearly as elevated, but how unusual is snowfall in this area?

In an attempt to answer this question, I reviewed the snow cover images like that above for November 1-16 from 1997-2009.  This web site from the National Climatic Data Center allows anyone to review these images for any date since 1997 (unless they happen to be missing).  I will admit this isn’t the most exact, scientific research, but given the limited resources and time, I think it’s a good estimate for understanding the extent of the current snow cover relative to normal.

In the 13 years the data are available, at no time from November 1-16 in any year was snow cover identified that far south and east in China.  In 2003, there was a brief area of snow cover near Beijing, around 38N latitude.  This is as far as any snow cover has extended south and east in China over the 13-year period until this year.  In fact, having reviewed all of the snow cover images from the beginning of November, I feel fairly confident the snow cover in north central and northeastern China is rare as well.  There were several years where even the Mongolian (between Russia and China, if you aren’t familiar) snow cover was negligible.

I expect we’ll see the extent of this snow cover recede in the coming days and weeks as temperatures rebound.  Given how unusual the snow cover is for much of the area, I don’t think it’s reasonable to expect it to last.  Still, we’ll watch it and be sure to continue comparing it to previous years.  It is quite interesting, to say the least.

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2 Responses to More on the Snow Cover in Asia

  1. Paul Yeager says:

    Very interesting post, Steve. I enjoyed your analysis, and I’ll keep reading for updates.

    I know that we talked about this before, but wouldn’t it be nice if there were a good global source like this that gave depth of snow cover.


    • Steve J says:

      Yes, it would be nice to have information about snow depth. Ideally a few decades worth so we can begin to judge above or below normal snowfall.

      With regard to Winter in the U.S., I’m still concerned about the lack of snow cover in southern Canada. I don’t see consistently cold temperatures in the country if there isn’t a near-constant source of reinforcing cold air to the North. It may be a little early to worry about it, but it does seem below normal relative to previous years. I’ll guess we’ll have answers soon enough.

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