ATOC 185 Lecture 6: Ice Storms
8 Jan 2019
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Chapter vi- ice storms: what are ice storms. Freezing rain: precipitation falling as liquid water into a layer of the air that is below. The water is supercooled and freezes upon impact. Water doesn"t necessarily freeze at 0 but ice melts at 0. For water to freeze ice nuclei (microscopic dust particles, soot, etc) must be present. Ice nuclei most effective at producing ice at temperatures less than -10*c. Few ice nuclei in small raindrops when temperatures are below 0 the drops supercool. Ice storms : caused by accumulation of freezing rain. Can halt air and ground transportation very devastating. Can weigh down and snap power lines and trees (when supercool water hits cold surfaces) Density of ice = 1 gram per cm3. Density of snow = 0. 1 gram per cm3. Mass= volume times density: basic principles of ice storms. Upward decrease in temperature with respect to height. Requires that a molecule cover a larger volume.
