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Pond and Lake Ice Safety

Posted: February 11, 2011

“How thick does the ice need to be for skating?”

You can find a really detailed answer to this question and more on the web at the Army Corps of Engineers’ Cold Regions research site.

Clear ice is stronger than white (bubble filled) ice. Four inches of clear ice will support 2000 pounds in a 30’ by 30’ space. It takes 8 inches of white ice to do the same thing.

Some cautions are in order at all times. Never skate alone. Provide rescue equipment – a rope that will float and a pole just in case of an emergency. If the ice is wet stay off until it has frozen again. Stay off ice that isn’t flat. For example if the pond level drops the ice will sink too but the ice touching the shoreline will be tilted and may not be able to support weight. Beware of areas with moving water such as inlets and outlets of ponds where the ice may be thin. Turn off diffused aeration systems in skating ponds. Bottom aeration systems create an upwelling of water which is warm enough to keep the ice open above the aerator.

A snow covered pond should be studied for wet spots in the snow. If there are none, clear the snow and skate; however if there are wet areas, they indicate that the ice beneath has been pushed down and submerged in water. Skating must wait until the slush has frozen adding more white ice to the pond.

Another hazard comes with snow covered ponds, not to skaters but to fish and other animals within the pond. The snow prevents light from penetrating the ice and stimulating the low level of photosynthesis that is needed to provide oxygen for fish and hibernating frogs and turtles. A winter kill of these animals may follow. Prevent winter kill by shoveling the snow from lanes across the pond. The bare ice in the lanes will allow enough light to pass through to stimulate a small amount of photosynthesis in the pond. Enough oxygen will be produced as a result to keep cold blooded animals alive. Another opportunity that a frozen pond presents is the chance to walk around with a tape measure. This is a good time to measure the area of the pond. The procedure is difficult to make clear with words alone, but you can “see” how to do it on the web at:

http://cumberland.extension.psu.edu/NResources/Pond%20Arithmetic.htm

Salt melts sidewalk ice and also provides grit to prevent slipping. However salt can corrode sidewalk surfaces and metal porch railings and can also damage flooring materials when tracked inside. Surface damage is best limited by early and frequent mechanical removal of snow and ice so that less salt is required. Sidewalk surfaces can be treated to resist corrosive effects of salt. Sand and sodium chloride have the least impact on carpeting – compared to calcium chloride and fertilizer salts. You can find more detailed information from this fact sheet from the University of Utah Cooperative Extension:

http://extension.usu.edu/files/publications/publication/HG-511.pdf