{{Short description, Irregular jagged ice formed over water
Jumble ice is a phenomenon that occurs when ice atop a river or other flowing body of water fractures due to the different flow rates beneath the ice. On a lake, pond, or other stationary body of water, ice forms undisturbed and generally does not move as long as the entire surface of the body of water is frozen. When a river freezes, water flow typically continues beneath the ice, exerting pressure on it. If the ice fractures, pieces of ice torn free by the river's current will collide with stationary or slower-moving pieces. After becoming stuck in place, the loosened pieces of ice refreeze irregularly, causing a rough, or ''jumbled'', surface.
In general, the faster a body of water flows beneath ice, the more likely it is to develop jumble ice. Temperatures near the freezing point also tend to cause jumble ice, as the higher temperatures weaken the ice structure, allowing for more pieces to be torn free before refreezing. The
Yukon River
The Yukon River ( Gwich'in: ''Ųųg Han'' or ''Yuk Han'', Yup'ik: ''Kuigpak'', Inupiaq: ''Kuukpak'', Deg Xinag: ''Yeqin'', Hän: ''Tth'echù'' or ''Chuu k'onn'', Southern Tutchone: Chu Nìikwän, russian: Юкон, Yukon) is a major watercour ...
in
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U ...
often exhibits jumble ice during the winter.
Jumble ice is a hazard for winter travelers, as the broken "ground" formed by the jumble ice can cause snowmachine accidents or injuries to
sled dog
A sled dog is a dog trained and used to pull a land vehicle in harness, most commonly a sled over snow.
Sled dogs have been used in the Arctic for at least 8,000 years and, along with watercraft, were the only transportation in Arctic areas ...
s.
See also
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Ice jacking
Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaqu ...