Frazil ice is a collection of loose, randomly oriented ice crystals millimeter and sub-millimeter in size, with various shapes, e.g. elliptical disks, dendrites, needles and of an irregular nature.[1][2][3][4][5] Frazil ice forms during the winter in open-water reaches of rivers as well as in lakes and reservoirs, where and when the water is in a turbulent state, which is, in turn, induced by the action of waves and currents. Turbulence causes the water column to become supercooled, as the heat exchange between the air and the water is such that the water temperature drops below its freezing point (in order of a few tenths of °C or less).[3][5][6] The vertical mixing associated with that turbulence provides enough energy to overcome the crystals' buoyancy, thus keeping them from floating at the surface. Frazil ice also forms in oceans, where windy conditions, wave regimes and cold air also favor the establishment of a supercooled layer.[7][8] Frazil ice can be found on the downwind side of leads and in polynyas. In these environments, that ice can eventually accumulate at the water surface into what is referred to as grease ice.
Frazil ice is notorious for blocking water intakes[6][9][10] as crystals accumulate and build up on the intake trash rack. Such blockages negatively impact water supply facilities, hydropower plants, nuclear power facilities, and vessels navigating in cold waters, and can lead to unexpected shut downs of the facility or even collapse of the trash rack.
- ^ Bukina, L.A. (1967). "Size distribution of frazil ice crystals in turbulent flows". Izvestiya, Atmospheric and Oceanic Physics. 3 (1). Translated by Keehn, P.A.: 58–68.
- ^ Gosink, J. P.; Osterkamp, T. E. (1983). "Measurements and Analyses of Velocity Profiles and Frazil Ice-Crystal Rise Velocities During Periods of Frazil-Ice Formation in Rivers". Annals of Glaciology. 4: 79–84. Bibcode:1983AnGla...4...79G. doi:10.3189/S0260305500005279. ISSN 0260-3055. S2CID 246047589.
- ^ a b Clark, Shawn; Doering, John (2008). "Experimental investigation of the effects of turbulence intensity on frazil ice characteristics". Canadian Journal of Civil Engineering. 35: 67–79. doi:10.1139/L07-086.
- ^ McFarlane, Vincent; Loewen, Mark; Hicks, Faye (2017). "Measurements of the size distribution of frazil ice particles in three Alberta rivers". Cold Regions Science and Technology. 142: 100–117. Bibcode:2017CRST..142..100M. doi:10.1016/j.coldregions.2017.08.001. ISSN 0165-232X.
- ^ a b Schneck, Christopher C.; Ghobrial, Tadros R.; Loewen, Mark R. (2019). "Laboratory study of the properties of frazil ice particles and flocs in water of different salinities". The Cryosphere. 13 (10): 2751–2769. Bibcode:2019TCry...13.2751S. doi:10.5194/tc-13-2751-2019. ISSN 1994-0416. S2CID 210569242.
- ^ a b Daly, Steven F. (March 1991). "Frazil Ice Blockage of Intake Trash Racks" (PDF). Cold Region Technical Digest (91–1). CRREL: Cold Regions Research and Engineering Laboratory, US ARMY Corp of Engineers: 1−14. OCLC 465638709. Archived from the original on 17 April 2012.
- ^ Wadhams, Peter (2000). Ice in the Ocean. CRC Press. ISBN 978-1-4822-8308-2.
- ^ Weeks, Willy (2010). On Sea Ice. University of Alaska Press. ISBN 978-1-60223-101-6.
- ^ Richard, Martin; Morse, Brian (2008-07-01). "Multiple frazil ice blockages at a water intake in the St. Lawrence River". Cold Regions Science and Technology. 53 (2): 131–149. Bibcode:2008CRST...53..131R. doi:10.1016/j.coldregions.2007.10.003. ISSN 0165-232X.
- ^ Daly, Steven F.; Ettema, Robert (August 2006). "Frazil Ice Blockage of Water Intakes in the Great Lakes". Journal of Hydraulic Engineering. 132 (8): 814–824. doi:10.1061/(asce)0733-9429(2006)132:8(814). ISSN 0733-9429.