Jumble ice
Encyclopedia
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
in Alaska
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
s.
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
Yukon River
The Yukon River is a major watercourse of northwestern North America. The source of the river is located in British Columbia, Canada. The next portion lies in, and gives its name to Yukon Territory. The lower half of the river lies in the U.S. state of Alaska. The river is long and empties into...
in Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
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
Snowmobile
A snowmobile, also known in some places as a snowmachine, or sled,is a land vehicle for winter travel on snow. Designed to be operated on snow and ice, they require no road or trail. Design variations enable some machines to operate in deep snow or forests; most are used on open terrain, including...
accidents or injuries to sled dog
Sled dog
Sled dogs, known also as sleigh man dogs, sledge dogs, or sleddogs, are highly trained types of dogs that are used to pull a dog sled, a wheel-less vehicle on runners also called a sled or sleigh, over snow or ice, by means of harnesses and lines.Sled dogs have become a popular winter recreation...
s.