What percent weaker is ice on a river vs. on a lake?

wendypj

I found two sources, one which only differentiates between salt and freshwater and the other which states that lakes and rivers can have the same kind of ice; it is external factors such as temperature, current and weather conditions which determine the strength of the ice. To that end, I guess that ice on a river isn't always weaker than ice on a lake, but neither is it always stronger...... http://ice-glaces.ec.gc.ca/App/WsvPageDsp.cfm?Lang=eng&lnid=10&ScndLvl=no&ID=10167 http://uregina.ca/~sauchyn/geog327/ice.html Nov 29 06, 5:03 AM

zbeckabee

Slush ice is half as strong as clear, blue ice. Slush shows weakening of the ice and should be considered a danger sign. Clear, blue river ice is 15 percent weaker than pond or lake ice. New ice is usually stronger than old ice because the bond between the ice crystals decay with age. Dark or honeycombed ice indicates deterioration and should be avoided. Even if a cold snap halts the deterioration process, dark or honeycombed ice will never refreeze to its original strength. Light winds accelerate formation of ice, while strong winds force water from beneath the ice and can decay the edges. Snow can insulate ice and keep it strong but it can also keep it from further freezing or hide cracked or weak ice or open-water areas. "Lakes with moving water should be viewed with skepticism" Satre says. "Water movement whether from an inlet, spring, outlet or groundwater seepage can retard freezing and leave hard-to-detect thin spots. "Ice forms at different rates," Satre says, "and can be a foot thick in one spot and an inch thick in another." According to ice strength figures compiled by the Lumbermen's Safety Association and other sources, 2-3 inches of clear, blue ice will support one person walking. General use such as ice fishing or skiing requires at least 4 inches of good ice, 5 inches for snowmobiling. At least 8 inches of solid ice is needed to support a car or light truck, 10 inches for medium trucks. Which reminds me of an e-mail I got this week about a frozen lake, two Wisconsin duck hunters, a dog, a brand new Lincoln Navigator and a stick of dynamite... http://www.siouxlandoutdoors.com/OutdoorsColumns/1999/12_26_99.html Nov 29 06, 6:11 AM