Editing Ice (section)

====Snow and freezing rain ====
{{Main|Snow|Snowflake}}
[[File:SnowflakesWilsonBentley.jpg|thumb|[[Snowflake]]s by [[Wilson Bentley]], 1902]]
Snow crystals form when tiny [[supercool]]ed cloud droplets (about 10&nbsp;[[μm]] in diameter) [[freezing|freeze]]. These droplets are able to remain liquid at temperatures lower than {{convert|-18|C|K F}}, because to freeze, a few molecules in the droplet need to get together by chance to form an arrangement similar to that in an ice lattice; then the droplet freezes around this "nucleus". Experiments show that this "homogeneous" nucleation of cloud droplets only occurs at temperatures lower than {{convert|-35|C|K F}}.<ref name=Mason>{{cite book|author = Mason, Basil John| publisher= Clarendon Press| isbn= 978-0-19-851603-3|year = 1971|title = Physics of Clouds|url = https://archive.org/details/physicsofclouds0000maso|url-access = registration}}</ref> In warmer clouds an aerosol particle or "ice nucleus" must be present in (or in contact with) the droplet to act as a nucleus. Our understanding of what particles make efficient ice nuclei is poor&nbsp;– what we do know is they are very rare compared to that cloud condensation nuclei on which liquid droplets form. Clays, desert dust and biological particles may be effective,<ref name=Christner2008>{{cite journal |last1=Christner |first1=Brent C. |last2=Morris |first2=Cindy E. |last3=Foreman |first3=Christine M. |last4=Cai |first4=Rongman |last5=Sands |first5=David C. |title=Ubiquity of Biological Ice Nucleators in Snowfall |journal=Science |date=29 February 2008 |volume=319 |issue=5867 |pages=1214 |doi=10.1126/science.1149757 |pmid=18309078 |bibcode=2008Sci...319.1214C |citeseerx=10.1.1.714.4002 |s2cid=39398426 }}</ref> although to what extent is unclear. Artificial nuclei are used in [[cloud seeding]].<ref>{{cite web|url=http://amsglossary.allenpress.com/glossary/search?p=1&query=cloud+seeding&submit=Search|title=Cloud seeding|author=Glossary of Meteorology|year=2009|access-date=28 June 2009|publisher=American Meteorological Society|url-status=dead|archive-url=https://web.archive.org/web/20120315161127/http://amsglossary.allenpress.com/glossary/search?p=1&query=cloud+seeding&submit=Search|archive-date=15 March 2012}}</ref> The droplet then grows by condensation of water vapor onto the ice surfaces.<ref>{{cite journal |last1=Pelley |first1=Janet |title=Does cloud seeding really work? |journal=Chemical and Engineering News|date=30 May 2016|volume=94 |issue=22 |pages=18–21 |url=http://cen.acs.org/articles/94/i22/Does-cloud-seeding-really-work.html |access-date=26 May 2024 |archive-date=10 November 2016 |archive-url=https://web.archive.org/web/20161110235130/http://cen.acs.org/articles/94/i22/Does-cloud-seeding-really-work.html |url-status=live}}</ref>

[[Ice storm]] is a type of winter storm characterized by [[freezing rain]], which produces a [[glaze ice|glaze]] of ice on surfaces, including roads and [[power line]]s. In the United States, a quarter of winter weather events produce glaze ice, and utilities need to be prepared to minimize damages.<ref>{{cite journal |last1=Sanders |first1=Kristopher J. |last2=Barjenbruch |first2=Brian L. |title=Analysis of Ice-to-Liquid Ratios during Freezing Rain and the Development of an Ice Accumulation Model |journal=Weather Forecasting |date=1 August 2016 |volume=31 |issue=4 |pages=1041–1060 |doi=10.1175/WAF-D-15-0118.1 |bibcode=2016WtFor..31.1041S }}</ref>