Author(s): Edward Kempema; Robert Ettema; Benjamin Mcgee
Keywords: No keywords
Abstract: This paper describes anchor ice formation in the Laramie River, a small river in Wyoming. Anchor ice in the Laramie River forms predominately in riffles at night, although minor amounts also form on sand substrates. Anchor ice crystals are large, indicating that in situ thermal growth is important. Anchor ice forms on the river’s bed, and, when released from the bed, rafts bed sediment downstream. The floating, released anchor ice is a major contributor to the river’s surface ice cover. A conceptual model for anchor ice formation is developed. This model suggests that water supercooled in pools supplies a heat sink that absorbs the latent heat of fusion of anchor ice growing in riffles. The net result is a non-uniform distribution of anchor ice on the bed. We discuss flow parameters important for determining anchor ice growth, and show how a substantial set of parameters influence anchor ice formation.