Tuesday, January 8, 2008

Snow Way

In December, the local daily newspaper had an article talking about the amount of snowfall we’d received, stating that around 20 inches had accumulated in 2007, the highest in seven years. They went on to say that 2006 had no snow at all, which really got my attention, since I remember that we had snow last winter. It was at that point that it struck me that the reporter had fallen prey to that all-too-common slip-up that the map is not the territory. This was yet another example of how our cultural categories, in this case our annual calendar, distorts reality.

Ask any bird, tree, river, or rock on the planet when the year begins or ends, and at best you’ll get a frightened look and at worst you’ll get stony silence or be completely ignored. All right, that’s pretty much true with just about any question you’d ask, but in this case, the coincidence is entirely appropriate, since the year doesn’t really begin or end at any particular time at all. Our planet just keeps going smoothly around the sun in its slightly elliptical orbit without any starting or stopping point along the way. The same goes with the seasons, as do the ways of nature. Our particular species has created a cultural overlay we like to call a “year” to mark one complete revolution around the sun, and in order to do so, have agreed upon Dec. 31/Jan. 1 to draw that invisible starting line in time. Of course, the Christian, Babylonian, Indian and old Roman calendars started their year after the spring equinox, the Egyptians started their year in summer, the Jewish calendar began after the fall equinox, and the Islamic calendar is lunar, meaning that the “beginning” moves throughout the solar year over time.

All of this is to say that deciding to “start” and “end” a year at a particular time cuts up a continuous process and distances us from reality as experienced by the rest of nature. In this case, it splits one season, namely winter, into 2 different years, so in order to get accurate views of this season, you have to do some additional mental gymnastics to get a clearer picture. It means combining the snowfall totals from October, November, and December of one year with January, February, March and April of the next year.

I emailed Jennifer Schack, Sunflower Cable meteorologist, to see if she could provide me with this information, and she said she had the monthly snowfall totals from January 2001 through December 2007, and generously shared those. I also poked around the internet and found that I could access the snowfall records from the Lawrence Coop Weather station (glamorously given the title: “144559”) from 1939-2003. I also found out that climatic averages are re-figured every 30 years or so, and that the current climatic averages are based on data collected from station 144559 between the years 1971-2000. Finally, in researching my book Wild Douglas County, I had used information from the Soil Survey of Douglas County, published in 1977. Collecting all of this information, I created a couple of tables, reproduced below:

Table 1: Snowfall averages for Lawrence, KS, 2001 to 2007 (Sunflower Cable data)

Month

00/01

01/02

02/03

03/04

04/05

05/06

06/07

07/08

Avg.*

Oct.

--

0

0

0

0

0

0

0

0

Nov.

--

0

0.1

0

5

0

0

0.1

0.85

Dec.

--

0

0.2

0.2

0

12

0

8.7

2.07

Jan.

3.2

5

5

0

3

0

3.2

--

2.7

Feb.

6.3

3

3.7

7

3

0

6.1

--

3.8

Mar.

1

3.8

0

0

0

0

0

--

0.63

Apr.

0

0

0

0

0

0

0.1

--

0.01

Total

10.5

11.8

9

7.2

11

12

9.4

8.8

10.07

* Using data only from complete seasons. If early 2001 and late 2007 included, avg is 11.38”

Looking at the data seasonally, it becomes readily apparent that the lack of snow in 2006 and the “highest totals in 7 years” both disappear, as both halves of the season are re-combined in a way that we—and all other forms of life experience winters. So are we receiving more snow than average this winter, i.e. Oct 2007 through April 2008? Maybe, maybe not. On the “maybe” side, the average first three months of snowfall in the past 7 years has been only 3.75 inches, and if you don’t include this year, it’s only 2.92” through December. On the “maybe not” side, however, the entire snowfall for the 2005/6 season (12”) came in December.

Putting these data collected by Sunflower Cable into a larger context, Table 2 below compares the data to a larger dataset collected over a longer period of time:

Table 2: Snowfall averages for Lawrence, KS using different datasets

Month

2001/2 to 2006/71

1971 to 2000 avgs.2

1939 to 2003 avgs3

SCS Climate avgs4

October

0.0

0.2

0.14

-

November

0.85

1.1

0.77

-

December

2.07

2.9

3.88

-

January

2.7

6.5

5.38

-

February

3.8

5.0

3.83

-

March

0.63

1.6

2.59

-

April

0.01

0.3

0.41

-

Total avg.

10.07

17.6

17.0

“18 to 20”

1Sunflower Cablevision weather station data

230 year avgs. from 144559 Lawrence, KS station (National Climate Data Ctr. website)

364 year avgs. from 144559 Lawrence, KS station (High Plains Climate Center website)

4Soil Survey of Douglas County, Climate description (published 1977), using data analyzed by Dean Bark, Kansas climatologist for the National Weather Service, using records that go back to 1868.

Looking at the longer datasets, it appears that if anything, we’ve been getting LESS snowfall in the past 6 years or so. Even if you include the incomplete data seasons of 2000 and 2007 and use the higher average of 11.38” it still looks like we used to get more snow than we have since the beginning of the new millennium. It’s interesting that the 30 year average is slightly higher than the 64 year total, though, even though it’s less than the sketchier 100-plus year records. Does global warming increase snowfall around here or decrease it? Are there other cycles at play, like the sunspot cycle? All good questions, but unanswerable by my cursory analysis. Like so much of our weather in these parts, the average is pretty theoretical when your standard deviation is so large. Suffice it to say that it looks like of late, the snowfall for a winter has been running between 8 and 12 inches, with the longer term average of at least 17 inches, so it even if we get twice much snow as we’ve already received for the seasonal total, we will be well within the long term normal range.

So if it snows some more, keep those bird feeders filled, enjoy the unifying effect a substantial snowfall has on the landscape, brush up on your track identification and learn about wildlife activities in your neighborhood. Enjoy the deep blue skies this time of year after a cold front has passed through, and if the snow is fresh and deep, get a glimpse of the cold blue shadows in the snow as you shovel. Don’t forget Eagles Day, and stay warm!