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Title: arctic sea smoke on Lake Winnipesaukee, New Hampshire View count: 509 Rating: 4.5 (2 ratings) Description: Arctic sea smoke occurs when there is very cold air blowing over much warmer water. The water gives off its heat to the air. Very cold air is usually very dry, so the body of water is usually giving off a good deal of moisture to the air as well -- thus rapidly cooling by evaporation. On New Hampshire's Lake Winnipesaukee this happens within a couple of weeks of the lake freezing in late December or early January. When the arctic sea smoke becomes thick enough, it can result in very light rime icing on windward shores. That's when water droplets visible in the air freeze to whatever they hit, when driven by the wind. It's more common on mountaintops and on aircraft wings in flight, but it can happen on the lake as well. Sometimes the lake contributes enough moisture to the air for very light lake effect snow to form. Freezing fog and local effect snow have occurred at Lake Winnipesaukee when the water was frozen, too. One night in January 2009, clear and calm conditions caused radiational cooling and temperatures dropped well below zero very quickly. The air above the lake reached its saturation point (dewpoint) and its moisture became visible as fog. The water below the lake ice was 33 degrees -- a lot warmer than the air above it. A fog settled over the frozen lake (which is surrounded by mountain ranges on three sides.) With the temperature below freezing, the fog froze to everything, forming feathers about a half-inch thick on everything by morning (see video: Camping in an Igloo on Lake Winnipesaukee.) That same night, the fog grew thick enough over the lake so that the excess moisture began to precipitate out as snow. There was 0.1" of snow the next morning at the Black Cat Island Weather Station (www.blackcatnh.com/weather). It came from the fog alone; there were no clouds above the fog, and surrounding mountaintops with elevations around 2000 feet were visible above the fog as seen from the weather station. It was snowing as the sun came up, but tapered off after the sun's heat made the fog dissipate. Tags: lake, winnipesaukee, new, hampshire, winter, arctic, sea, smoke, cold, water, weather, phenomenon, phenomena, physics, Author: blackcatnh |
