As we rake the fallen leaves and prepare for winter, we wonder what kind of a winter it will be. Research and weather data review tell us that the New England winters are changing. A 2008 report by University of New Hampshire researchers showed that over the past 40 years, for each ten year period, New Hampshire winter temperatures rose roughly half of one degree and the number of snow-covered days reduced by nine days. Snowfall also decreased by two inches every ten years. The study also showed that January and February showed the most warming of all the months. So, is winter disappearing?
The snow cover changes might be due to what is called the “snow-albedo feedback loop” effect, in which decreased snow means less reflected sunlight, which in turn means more snow melt, thereby decreased snow cover, and so it continues on. These trends still allow for snowy winters, and periods of cold snaps, but overall the data is clear. These studies continue locally at the UNH Center for Climate Change Research Center to better understand the changing patterns surrounding us.
New Hampshire lakes still can be expected to ice over, although ice-in is later and ice-out is earlier, reducing the total days we can expect the waterbodies to be covered by ice and thereby “resting”. Less ice cover means more light shines down into the lake changing the ecosystem’s behavior, giving some species more energy to grow or multiply, rather than being in “rest” mode. Limnologists are tracking what this means in terms of lake ecosystem adaptation and change.
However, ice is still a prominent feature of New England lakes. Anyone who has been out on a frozen lake has experienced the “crack” sound and sudden splinter in the ice sheet. During warming and cooling temperature cycles, the ice sheet expands and contracts, pushing toward and onto the shore or shrinking and cracking. The cracks fill with water which then freezes. Repetition of this cycle can results in the ice sheet moving slowly outward by several feet, piling up at the edges. On Lake Sunapee and other large water bodies, ice out is a period during which wind can also move ice plates around considerably.
Recently I ran across a 1979 Popular Science article in which lake bubblers were discussed as a solution to dock protection during all this aforementioned contortion of lake ice formation and reformation. Apparently prior to de-icers, ice around a dock was managed by “periodically cutting a channel around docks to keep the ice thin enough to avoid damage.”
The first bubbler systems had gentle movement bringing warm water to the surface. The purpose was to maintain a small area of thin ice or open water around the dock. Some systems even used windmills for power. Technology has come forward to enable timers to be used, along with thermostats, to control the bubblers, or de-icers as they are now known, allowing a minimum of disturbance to the lake’s ecosystem, while preventing dock damage. These technologies enable minimum noise for the neighbors and less open water, minimizing hazards to those who enjoy being out on the lake in winter. They also allow for less sediment to be stirred up and for the lake to “rest” naturally. We might say those technologies are “icing on the lake”.
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