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Thursday, March 26, 2015

How a Lake Thaws

It’s officially spring and the temperatures are beginning to warm up. With temperatures above freezing, we’re patiently waiting for the ice on Lake Wallenpaupack to thaw so we can get docks and boats ready for the upcoming season and back into the water at Lighthouse Harbor Marina. As previously explained in our “How a Lake Freezes” blog, lakes freeze starting at the top and going down. So it’s no surprise that a lake thaws starting at the bottom and coming up!

Once there is no snow left on the top of the lake, the sun can directly penetrate the ice. Acting like glass in a greenhouse, the ice insulates the water below and allows it to warm up which melts the deepest layers of ice first. As the ice thins to about 4-12 inches it converts into “candles” (long vertical crystals) which conduct light even more. This causes the ice to appear black because it’s not reflecting much sunlight.

The light energy is being transferred to the underlying water which increases its temperature. The crystals break apart as water fills in between them causing more reflection and making the ice appear grayish. This thin layer of ice crystals on the surface of the lake is easily broken up by wind and blown around the lake causing water to reemerge.

The warm temperatures, along with the rain expected today, will help this thawing process and will hopefully melt most of the ice on the lake. Once the lake is thawed out we’re one step closer to summer and boating season!

thawing-lake-ice

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