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Summertime in the BelgradesContentsfor Printing
Article Summaries |
Ice-Out: Many Meanings
Every spring, with a whoosh or a whisper, the winter's ice breaks up, disappears, goes "out," and once again the lakes are open water — but not before this rite of passage has attracted more speculation, more anticipation, and even more lotteries than other changes of season. Historically, ice-out impacted such major industries as ice harvesting, shipping, and spring river drives for logs that had been cut and stored all winter. When ice was harvested on the Kennebec River and sent on clipper ships around the world many livelihoods were at stake, while on a much smaller scale, individuals and businesses depended on ice harvested from lakes and ponds and stored in icehouses, in sawdust, for use throughout the summer. Today, ice-out's major impact is on recreation, especially fishing — both ice and open water, but also snowmobiling, ATVing, skiing, and skating, and, as always, water sports and the opening of camps. 
From a scientific point of view ice leaves the lake when the lake water is saturated with air at a temperature close to 0° C (32° F), and the concentration of oxygen is nearly constant at about 13 mg/L from the lake surface to the lake bottom. After ice-out, the surface water warms to 4° C (39° F) and, since it is heavier than the cooler water below, sinks to the bottom. This process of turnover, or mixing, enables nutrients from the bottom sediments to be carried to the surface to nourish algae and other plant life, and replenishes oxygen in the deep bottom waters where many fish species live. The guess value of ice-out can be big stakes. In Alaska, one lottery allegedly brings in several million dollars. Closer to home, Joe's Pond in West Danville, Vermont realizes up to $10,000 annually in a 50/50 $1-a-ticket contest that attracts participants from 38 states and seven countries. In the twenty years the contest has been run, the ice has gone out as early as April 16 and as late as May 8. The contest is sponsored by the lake association to fund 4th of July fireworks. In most cases ice-out is determined when a special devise set up on the ice tips over as the ice sinks under it. However, on Lake Winnipesaukee in New Hampshire, where the shorefront is 182 miles, ice-out is determined when all 38 islands (of the total 274) on the U.S. Mailboat route are ice-free. As thawing progresses, a plane makes twice daily flyovers and when all the delivery islands appear accessible the Mail Boat attempts a run. If it is successful, that date is considered Ice-Out Day. 
When does ice-out usually happen? The average date in the Belgrades both by unofficial records and old-timer recollection tends to be about April 19 or 20, which it was this year on Great Pond. On China Lake, where more accurate records have been compiled, of 128 years, 120 had ice-outs in April. The farther north, of course, the later the date. In the Rangeley Lakes the average ice-out occurs the first week in May. The earliest date of ice-out, recorded by the Union Water Power Company, was April 14, 1945, the latest May 24, 1882. In 115 years, ice-out occurred in April only 19 times. 1954-1967 was the longest stretch of May ice-outs, 14 years. The greatest range was between 1920 (May 19) and 1921 (April 14), a difference of 35 days. A similar range, 38 days (not consecutively), was recorded on Green Lake near Bangor, where ice-out variables were used to analyze the lake's growing season and oxygen in the lower level of water (the hypolimnion). Study results indicate that comparisons in any kind of measurement in the lake from one year to any other year should be based on a time scale using the ice-out date for that particular year as the origin. Humans aren't the only species to check ice-out from the air. Loons do it, too. Males, anxious to claim their territory for the summer, make pre-ice-out flyovers from the coast, an ambitious but fast excursion considering they can fly up to ninety miles an hour. That's how, like magic, they appear on the lakes the day after the ice leaves. In a state where Mother Nature pretty much tells everyone what to do and when to do it, the ice-out message is: get out the boats and the open water fishing gear, and let the summer begin. | ||