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{{Short description|Device claimed to stop hail}} |
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[[Image:Hail cannon.jpg|thumb|right|Hail cannon in 2007]] |
[[Image:Hail cannon.jpg|thumb|right|Hail cannon in 2007]] |
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[[Image:International congress on hail shooting.jpg|thumb|right|Hail |
[[Image:International congress on hail shooting.jpg|thumb|right|Hail cannons in 1901]] |
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[[Image:Banska Stiavnica Cannon-1.JPG|thumb|right|Hail cannon in [[Banská Štiavnica]] Old Castle (Slovakia). Probably designed by Julius Sokol]] |
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| ⚫ | A |
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A '''hail cannon''' is a [[shock wave]] generator claimed to disrupt the formation of [[hailstones]] in the [[atmosphere]]. |
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These devices can engender conflict between farmers and neighbors when used, as those who have purchased such an expensive device defend the [[pseudoscience]] behind its function at risk of being taken for a fool by [[snake oil]] merchants.{{Citation needed|date=December 2010}} The cause of the conflict arises from the fact that the [[machine|device]]{{Citation needed|date=December 2010}} is repeatedly fired every 1 to 10 seconds over the period when the storm is approaching and until it has passed through the area. Manufacturers claim that what would otherwise have fallen as hail stones then falls as slush or rain. It is said to be critical that the machine is running during the approach of the storm in order to affect the developing hail stones, although all manufacturers unanimously agree that the area of effect of their device is only 100 to 200 square meters directly above. Dating back to the 18th century, modern '[[radar]] controlled [[systems]]' are nowadays available to replace human operation of the unit. |
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These devices frequently engender conflict between farmers and neighbors when used,<ref>{{cite web |last=Case |first=Bert |date=2005-07-18 |title=Residents Protest Hail Cannons"Residents Protest Hail Cannons |publisher=[[WLBT]] |url=http://www.wlbt.com/story/3608868/residents-protest-hail-cannons/ |access-date=2018-09-13}}</ref> because they are loudly and repeatedly fired every 1 to 10 seconds while a storm is approaching and until it has passed through the area, yet there is no [[scientific evidence]] for their effectiveness.<ref>{{cite web |last1=Self |first1=Douglas |title=Hail Cannon |url=http://www.douglas-self.com/MUSEUM/COMMS/hailcan/hailcan.htm |website=Museum of Retrotech |publisher=Douglas Self |access-date=28 May 2020}}</ref> |
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==Historical use== |
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In the French wine-growing regions, church-bells were traditionally rung in the face of oncoming storms<ref>{{cite news |date=1905-09-30 |title='Hail Cannons' of France |publisher=[[Southland Times]] |volume=30 |issue=19676 |url=https://paperspast.natlib.govt.nz/newspapers/ST19050930.2.73 |access-date=2018-09-13}}</ref> and later replaced by firing rockets or cannons.<ref>{{cite magazine |date=June 1909 |title=Do cannons and rockets dispel hail storms? |magazine=Popular Mechanics |issn=0032-4558 |publisher=Hearst Magazines |page=548}}</ref> |
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==Modern systems== |
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| ⚫ | A mixture of [[acetylene]] and [[oxygen]] is ignited in the lower chamber of the [[machine]]. As the resulting blast passes through the neck and into the cone, it develops into a [[shock wave]]. This shock wave then travels through the cloud formations above, a disturbance which manufacturers claim disrupts the growth phase of hailstones. |
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Manufacturers claim that what would otherwise have fallen as hailstones then falls as slush or rain. It is said to be critical that the machine is running during the approach of the storm in order to affect the developing hailstones. One manufacturer claims that the radius of the effective area of their device is around {{cvt|500|m}}.<ref>{{cite web |last1=Egger |first1=Mike |title=How it works |url=https://www.hailcannon.com/how_it_works.html |website=Hail Cannon Manufacturer |publisher=Mike Eggers Ltd Nelson New Zealand |access-date=28 May 2020}}</ref> |
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==Scientific evidence== |
==Scientific evidence== |
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There is |
There is no evidence in favor of the effectiveness of these devices. A 2006 review by Jon Wieringa and Iwan Holleman in the journal ''Meteorologische Zeitschrift'' summarized a variety of negative and inconclusive scientific measurements, concluding "the use of cannons or explosive rockets is a waste of money and effort".<ref>{{cite journal |last1=Wieringa | first1=Jon |last2=Holleman | first2=Iwan |date=2006-12-20 |title=If cannons cannot fight hail, what else? |journal=Meteorologische Zeitschrift |doi=10.1127/0941-2948/2006/0147 | bibcode=2006MetZe..15..659W |volume=15 |number=6 |pages=659–669 |url=http://www.knmi.nl/publications/fulltexts/hailcannons2_preprint.pdf |archive-url=https://web.archive.org/web/20150828101449/http://www.knmi.nl/publications/fulltexts/hailcannons2_preprint.pdf |archive-date=2015-08-28 }}</ref> |
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There is also reason to doubt the efficacy of hail cannons from a theoretical perspective.<ref>{{cite web |last=Curran |first=John |date=2008-09-22 |title=Vt. orchard wakes the neighbors with hail cannon |website=[[Fox News]] |agency=Associated Press |url=http://www.foxnews.com/printer_friendly_wires/2008Sep22/0,4675,HailCannon,00.html |access-date=2018-09-13}}</ref> For example, thunder is a much more powerful sonic wave, and is usually found in the same storms that generate hail, yet it does not seem to disturb the growth of hailstones. Charles Knight, a cloud physicist at the [[National Center for Atmospheric Research]] in [[Boulder, Colorado]], said in a July 10, 2008, newspaper article that "I don't find anyone in the scientific community who would validate hail cannons, but there are believers in all sorts of things. It would be very hard to prove they don't work, weather being as unpredictable as it is." |
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==See also== |
==See also== |
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* [[Cloud seeding]] |
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* [[Cloudbuster]] |
* [[Cloudbuster]] |
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* [[Pseudoscience]] |
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== |
==References== |
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{{Reflist}} |
{{Reflist}} |
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==External links== |
==External links== |
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{{commonscat |
{{commonscat|Hail cannons}} |
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* [http:// |
* [http://www.hail.org/map/NOAA.html Hail Storms by NOAA on Google Maps] |
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* {{cite journal |last1=Changnon | first1=Stanley A. Jr |last2=Ivens | first2=J. Loreena |date=March 1981 |title=History Repeated: The Forgotten Hail Cannons of Europe |journal=Bulletin of the American Meteorological Society | eissn=1520-0477 |publisher=Illinois State Water Survey |location=Champaign, Ill |doi=10.1175/1520-0477(1981)062<0368:HRTFHC>2.0.CO;2 |bibcode=1981BAMS...62..368C |volume=62 |number=3 |page=368|doi-access=free }} |
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* Wieringa, J. and Iwan Holleman, [http://www.knmi.nl/publications/fulltexts/hailcannons2_preprint.pdf If cannons cannot fight hail, what else?], ''Meteorologische Zeitschrift'', '''15''', issue 3, June 2006. |
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* [http://www.benningtonbanner.com/ci_9884731 'Hail cannon' opponents decry its use], ''Bennington Banner'', Neal P. Goswami, July 15, 2008. |
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* [http://www.rockymountainnews.com/drmn/local/article/0,1299,DRMN_15_4833500,00.html Cannons both hailed and blasted], Rocky Mountain News, July 10, 2006. |
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* [http://ams.allenpress.com/archive/1520-0477/62/3/pdf/i1520-0477-62-3-368.pdf History Repeated: The Forgotten Hail Cannons of Europe (pdf)], Bulletin of the American Meteorological Society, Volume 62, Issue 3 (March 1981) |
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* [http://www.npr.org/templates/story/story.php?storyId=9189996 NPR story on hail cannons] |
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* [http://www.anti-grele.fr/antihail_shockwave-generator.htm Shock waves generator animation] |
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* [http://www.meteo-radar.com/us/anti-hail_protection.htm Weather radar for hail storms detection] |
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{{DEFAULTSORT:Hail Cannon}} |
{{DEFAULTSORT:Hail Cannon}} |
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[[Category:Meteorological instrumentation and equipment]] |
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[[Category:Weather modification]] |
[[Category:Weather modification]] |
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[[Category:Shock waves]] |
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[[Category:Hail]] |
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[[es:Cañón granífugo]] |
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[[fr:Canon anti-grêle]] |
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[[nl:Hagelkanon]] |
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[[ro:Tun sonic]] |
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Latest revision as of 04:28, 18 December 2024
A hail cannon is a shock wave generator claimed to disrupt the formation of hailstones in the atmosphere.
These devices frequently engender conflict between farmers and neighbors when used,[1] because they are loudly and repeatedly fired every 1 to 10 seconds while a storm is approaching and until it has passed through the area, yet there is no scientific evidence for their effectiveness.[2]
Historical use
[edit]In the French wine-growing regions, church-bells were traditionally rung in the face of oncoming storms[3] and later replaced by firing rockets or cannons.[4]
Modern systems
[edit]A mixture of acetylene and oxygen is ignited in the lower chamber of the machine. As the resulting blast passes through the neck and into the cone, it develops into a shock wave. This shock wave then travels through the cloud formations above, a disturbance which manufacturers claim disrupts the growth phase of hailstones.
Manufacturers claim that what would otherwise have fallen as hailstones then falls as slush or rain. It is said to be critical that the machine is running during the approach of the storm in order to affect the developing hailstones. One manufacturer claims that the radius of the effective area of their device is around 500 m (1,600 ft).[5]
Scientific evidence
[edit]There is no evidence in favor of the effectiveness of these devices. A 2006 review by Jon Wieringa and Iwan Holleman in the journal Meteorologische Zeitschrift summarized a variety of negative and inconclusive scientific measurements, concluding "the use of cannons or explosive rockets is a waste of money and effort".[6]
There is also reason to doubt the efficacy of hail cannons from a theoretical perspective.[7] For example, thunder is a much more powerful sonic wave, and is usually found in the same storms that generate hail, yet it does not seem to disturb the growth of hailstones. Charles Knight, a cloud physicist at the National Center for Atmospheric Research in Boulder, Colorado, said in a July 10, 2008, newspaper article that "I don't find anyone in the scientific community who would validate hail cannons, but there are believers in all sorts of things. It would be very hard to prove they don't work, weather being as unpredictable as it is."
See also
[edit]References
[edit]- ^ Case, Bert (2005-07-18). "Residents Protest Hail Cannons"Residents Protest Hail Cannons". WLBT. Retrieved 2018-09-13.
- ^ Self, Douglas. "Hail Cannon". Museum of Retrotech. Douglas Self. Retrieved 28 May 2020.
- ^ "'Hail Cannons' of France". Vol. 30, no. 19676. Southland Times. 1905-09-30. Retrieved 2018-09-13.
- ^ "Do cannons and rockets dispel hail storms?". Popular Mechanics. Hearst Magazines. June 1909. p. 548. ISSN 0032-4558.
- ^ Egger, Mike. "How it works". Hail Cannon Manufacturer. Mike Eggers Ltd Nelson New Zealand. Retrieved 28 May 2020.
- ^ Wieringa, Jon; Holleman, Iwan (2006-12-20). "If cannons cannot fight hail, what else?" (PDF). Meteorologische Zeitschrift. 15 (6): 659–669. Bibcode:2006MetZe..15..659W. doi:10.1127/0941-2948/2006/0147. Archived from the original (PDF) on 2015-08-28.
- ^ Curran, John (2008-09-22). "Vt. orchard wakes the neighbors with hail cannon". Fox News. Associated Press. Retrieved 2018-09-13.
External links
[edit]
Wikimedia Commons has media related to Hail cannons.
- Hail Storms by NOAA on Google Maps
- Changnon, Stanley A. Jr; Ivens, J. Loreena (March 1981). "History Repeated: The Forgotten Hail Cannons of Europe". Bulletin of the American Meteorological Society. 62 (3). Champaign, Ill: Illinois State Water Survey: 368. Bibcode:1981BAMS...62..368C. doi:10.1175/1520-0477(1981)062<0368:HRTFHC>2.0.CO;2. eISSN 1520-0477.