https://wiki.sarg.dev/index.php?action=history&feed=atom&title=Snow_rollerSnow roller - Revision history2026-07-22T13:18:40ZRevision history for this page on the wikiMediaWiki 1.44.2https://wiki.sarg.dev/index.php?title=Snow_roller&diff=782123&oldid=previmported>TypoEater: /* top */ Fixed sloppy grammar in hatnote2024-11-26T14:53:57Z<p><span class="autocomment">top: </span> Fixed sloppy grammar in hatnote</p>
<p><b>New page</b></p><div>{{Short description|Large snowball formed by wind action}}<br />
{{About|the meteorological phenomenon|the snow compaction device|Snow road#History{{!}}Snow road|the movie|Sällskapsresan 2 – Snowroller}}<br />
[[File:Snow Roller in Rocky Mountain National Park.jpg|thumb|upright=1.35|Snow roller in [[Rocky Mountain National Park]]]]<br />
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{{Weather}}<br />
A '''snow roller''' is a rare [[meteorological]] phenomenon in which cylindrical [[snowball]]s are formed naturally as chunks of [[snow]] roll down hill or are blown along the ground by [[wind]], picking up further snow along the way, in much the same way that the large snowballs used in [[snowman|snowmen]] are made. They can be as small as a tennis ball, but they can also be bigger than a car.<ref name="Wireobot" /> Most snow rollers are a few inches or centimeters wide.<ref name="NatGeo" /><br />
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Alternative names for snow rollers include: '''snow bales''',<ref name="BBC 2019"/> '''snow donuts''', '''snownuts''' and '''wind snowballs'''.<ref name="NatGeo" /> Unlike snowballs made by people, snow rollers are typically [[cylindrical]] in shape, and are often hollow since the inner layers,<ref name="NatGeo">{{cite web|last1=Zachos|first1=Elaina|title=Why Snow Is Forming Donut-shape Spirals in Canada|url=https://news.nationalgeographic.com/2018/02/snow-rollers-wind-phenomenon-ottawa-canada-spd/|archive-url=https://web.archive.org/web/20180214010336/https://news.nationalgeographic.com/2018/02/snow-rollers-wind-phenomenon-ottawa-canada-spd/|url-status=dead|archive-date=February 14, 2018|publisher=[[National Geographic]]|accessdate=April 20, 2018|date=13 February 2018}}</ref> which are the first layers to form, are weak and thin compared to the outer layers. The inner sections can easily be blown away, leaving what looks like a [[doughnut]] or [[Swiss roll]].<br />
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Several conditions are needed for snow rollers to form:<br />
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* There must be a relatively thin surface layer of wet, loose snow, with a temperature near the [[melting point]] of ice.<ref name="NatGeo" /><br />
* Under this thin layer of wet snow there must be a substrate to which the thin surface layer of wet snow will not stick, such as ice or powder snow.<ref name="NatGeo" /><br />
* The wind must be strong enough to move the snow rollers,<ref name="NatGeo" /> but not strong enough to blow them apart.<br />
* Alternatively, gravity can move the snow rollers as when a snowball, such as those that will fall from a tree or cliff, lands on a steep hill and begins to roll down the hill.<ref name="NPRradio">{{cite news|title=Snow Doughnuts Are the Real Thing|url=https://www.npr.org/templates/story/story.php?storyId=8993287|website=NPR.org|publisher=[[National Public Radio]]|accessdate=April 20, 2018|language=en}}</ref><br />
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Because of this last condition, snow rollers are more common in hilly areas.<ref name="Wireobot">{{Cite news|url=http://wireobot.com/snow-roller/|title=Snow Donut or Snow Roller a rare interesting natural phenomenon - Wireobot|date=2016-10-27|newspaper=Wireobot|language=en-US|access-date=2016-10-27|url-status=live|archiveurl=https://web.archive.org/web/20161028020436/http://wireobot.com/snow-roller/|archivedate=2016-10-28}}</ref> However, the precise nature of the conditions required makes them a very rare phenomenon.<ref name="NPRradio" /><ref>{{Cite web|url=https://www.holzhau.de/1917-41-0-einzigartiges-naturschauspiel-zwischen-ortsteilen-clausnitz-bienenm%C3%BChle.html|title=Einzigartiges Naturschauspiel zwischen den Ortsteilen Clausnitz und Bienenmühle {{!}} Holzhau Rechenberg-Bienenmühle Clausnitz {{!}} 03.02.2019|last=Holzau|first=Tino Bellmann @ BCS Computersysteme Holzhau|website=www.holzhau.de|language=de|access-date=2019-02-03}}</ref><ref name= "BBC 2019">{{Cite news|url=https://www.bbc.co.uk/news/uk-england-wiltshire-47108382|title=Rare snow rollers spotted in field near Marlborough|date=3 February 2019|work=BBC News|accessdate=3 February 2019 }}</ref><br />
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==Gallery==<br />
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<gallery class="center" mode=nolines widths="200" heights="200"><br />
File:Snow Roller.jpg|Snow roller with a gear-like shape from [[Rocky Mountain National Park]], Colorado<br />
File:Rolling snow.JPG|Snow roller in the [[Giant Mountains]], in the Czech Republic near [[Poland]]<br />
File:Snow rollers in Venus PA, USA.jpg|Snow rollers formed overnight during high winds in Venus, [[Pennsylvania]]<br />
File:snowroller.jpg|A snow roller in [[Cincinnati]], Ohio, United States<br />
File:Schneeringe1 Foto Kathrin Spiegler.JPG|Snow rollers leaving tracks in the snow<br />
File:Snow roller Illinois.jpg|Snow rollers at [[Lincoln Christian College]], Illinois<br />
File:Umgeworfene Schneerige 4 Foto Olaf Parnieske.JPG|Snow rollers in [[Saxony-Anhalt]], Germany<br />
</gallery><br />
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== See also ==<br />
*{{annotated link|Yukimarimo}}<br />
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==References==<br />
{{commons category|Snow rollers}}<br />
{{reflist}}<br />
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[[Category:Snow or ice weather phenomena|Roller]]</div>imported>TypoEater