Research Report #12 — White Christmas
For many years scientists and naturalists have been studying and observing the flora and fauna of the Shawangunk Ridge. Foremost among them was Daniel Smiley, for whom Mohonk Preserve’s Daniel Smiley Research Center is named. Dan wrote numerous reports summarizing his observations on various topics. This regularly occurring series will feature some of these reports; some hold tremendous scientific value today and just await an interested researcher to follow up, others showcase a quirky sense of humor or highlight an oddity of nature.
Read the report: “A White Christmas.” Winter, 1976–1977. Daniel Smiley.
A Note from Paul Huth, Director of Research Emeritus:
This Research Report, written over 40 years ago, appeared in The Mohonk Trust’s Newsletter №31, Winter 1976–1977, and illustrates both the times, and interest in the records of the Mohonk Lake Cooperative Weather Station. The Weather Station had just completed its 80th year of continuous operation (1896–1976). Daniel Smiley, as Observer, was always interested in what the long term study of weather could reveal, and how weather events and possible trends affect Shawangunk plants and animals and the Shawangunk ecosystem.
Over the decades, collecting daily weather observations with Dan and serving as National Weather Service Official Weather Observer at the Mohonk Station after Dan, it was clear that the application of the long term weather record to answer questions from the public and researchers was a satisfying use of the data. Today, recent and current monthly weather sheets are now available on Mohonk Preserve’s website. For Preserve Conservation Science staff to answer a research question about a temperature or precipitation variable on a certain date is possible digitally as compared to the time consuming manual effort necessary when these original reports were written.
One of the regular daily measurements in the official daily weather record during the “winter” season (which we define as November through April), is “snow on ground”, measured to the nearest inch. This is different from 24 hour snowfall, which may be the same amount, but snow on ground mostly increases with additional snowfall or declines between precipitation events as the snow naturally settles, sublimates, condenses, and melts with above freezing temperatures. Snow on ground, or the snow pack, is a very dynamic internally changing system which will be the focus of a future Research Report Blog.
As Dan said in the beginning of this report, “One of the questions most frequently heard at the Mohonk Lake Weather Station is, What are the chances for a white Christmas?” Dan was clear that this idea was derived from a romanticized “picture of what a New England village….ought to look” like. But, curious about the larger weather context, he took a look at snow on ground measurements on December 25 for the 80 years of record. It revealed there were 46 years of the 80 years, or 58% that had snow on the ground. The average depth of snow for the years that had snow on ground was 5.6 inches. While for 8 years it was recorded as snowing on the day, for 10 of the years it rained on Christmas day. In some cases in the early weather sheets, snow on ground hadn’t been recorded, even though snow had fallen a few days previously and the temperatures were cold enough for it to remain. In those cases, Dan made a logical assumption that there was likely snow on the ground.
Of particular note were the record snow years! The year with the most snow on ground on December 25th was 1970, with 19 inches. The second year was 1966, with 16 inches. Those records still hold today.
Looking at the full 121 years of December 25th records, including the 41 years since Dan prepared his summary, is revealing. Now, 75 of the 121 years record snow on the ground, or 62% of the years. Those with snow falling on the day increased from the 8 that Dan noted in the first 80 years of record to 13 additional years over the next 41 years. During the same 41 years it rained on 8 days, where Dan had found 10 days in the first 80 years.
Read the report: “A White Christmas.” Winter, 1976–1977. Daniel Smiley.
