Ice in the northern streams of the United States

TitleIce in the northern streams of the United States
Publication TypeConference Proceedings
Year of Conference1940
AuthorsParsons, W. J.
Conference Name8th Annual Western Interstate Snow Survey Conference
Series TitleProceedings of the 8th Annual Western Interstate Snow Survey Conference
Date PublishedJune 1940
PublisherAmerican Geophysical Union, Transactions, Part III-B:
Conference LocationSeattle, Washington
KeywordsIce - Frazil, Ice - river

River water is cooled by the air but temperatures are kept almost uniform by turbulence. Needle-like crystals of ice form on the surface and act in one of 3 general ways. The crystals are carried below the surface in turbulent streams as a mixture of ice crystals and water called Frazil ice. The ice crystals join to form floating islands of ice in less turbulent streams. These pans of ice float to shore, unite with others to form an ice cover over the stream. A clear sheet of ice forms from the floating ice island in quiet streams. The rate of freezing decreases when an ice cover forms because of friction of ice surface. The ice under the surface soon melts smooth, reducing the friction. Pressure caused by ice expansion usually results in buckling in weak areas but bridge piers, bulkheads, and sea-walls can be damaged. Ice melts from the surface in spring. the melt-water seeps through cracks forming a honeycomb structure which is disrupted by the rising spring flow.