Talk:Hail

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Largest Hail Stone[edit]

The section detailing the 'largest hailstones' is incorrect.

According to the national geographic... http://news.nationalgeographic.com/news/2003/08/0804_030804_largesthailstone.html

The largest hailstone in US history fell in Nebraska and was 17.8cm wide. There is no mention of it being the largest in the world and I doubt it is.

Hail stones the size of footballs (Rugby League balls) were reported and shown on tv during a major hailstorm in Brisbane, Queensland during the 1980s. I don't recall anyone suggesting at the time that those were the largest hailstones in recorded history, but they were certainly larger than the stones detailed in this article.

The BBC says the largest hail stone was 1Kg and fell on Bangledesh.

http://www.bbc.co.uk/cbbc/eurekatv/big_hailstones.shtml

As a result of this evidence I have removed references to anything being the 'largest'.

Yea, do you go by weight or by size or what. Probably safer this way. --Fujita 18:49, 8 May 2007 (UTC)

Well the record is for the largest verified hailstone found in the U.S. Any stones that are larger must be confirmed and standardized measurements taken so that different stones can readily be compared. I know of no larges hailstones that have gone through such an officiating process. Epistemically speaking, undoubtedly larger hailstones have fallen, it's a matter of finding the hailstone, and once found, of having it authoritatively measured and recorded. There's a lot of empty space out there and a decent chance that even something which is found will not be verified.
As for the standardized measurements, what measurements are taken matters, they must be uniform, and account for the irregularity of hailstone shapes. Thus, it's circumference and weight that tends to be used. The Coffeyville KS and Aurora NE hailstone in the US met the world record for diameter and circumference, but a 1986? Bangladesh stone was reportedly heavier than those. Additionally, the 1970 Coffeyville stone was actually heavier than the Aurora stone from 2003; although the latter was larger in circumference and diameter.
Further complicating this, there was known to be significant melting for the Aurora hailstone and a large chunk of it broke off when hitting the gutter of a house. The Aurora area hailstones, initially reported as volleyball size (a size potential which was supported by algorithms mostly incorporating the thermodynamic environment), produced damage of holes in the roofs of farm houses that were large enough for adult males to crawl through. Evolauxia (talk) 03:34, 16 April 2008 (UTC)


"The largest hailstone ever recorded fell on 22nd June 2003, and measured 7 inches in diameter (17.8 centimeters) and 18.75 inches (47.6 centimeters) in circumference, this is equivalent to almost the size of a football. The stone was from a severe storm that affected the area of south-central Nebraska, and was discovered in the town of Aurora. The stone was preserved by local residents and then transported to the National Center for Atmospheric Research in Boulder, Colorado, where it will be preserved indefinitely. Although this may be the largest hailstone, it is not officially the heaviest as approximately 40% of the stone was missing from an impact with a house gutter as it fell. The heaviest hailstones on record fell in Gopalganj, Bangladesh, on the 14 April 1986 and weighed over 1 kilogram, they are reported to have killed 92 people." — Preceding unsigned comment added by 67.71.145.31 (talk) 20:38, 5 September 2011 (UTC)

== how does hail form hail forms by updrafts within thunderstorm pushrain high into cloud where very cold air freezes it once is frozen it starts to fall but gets caught in another strong updrate where it gathers more moister and more moisture. jocelyne lemus waz here ==

Green?[edit]

I've heard that tornado producing clouds tend to have a greenish color, but hail? I've had hail here and the sky was dark, but definately not "green colourat[ed]"... 68.39.174.238 01:29, 31 March 2006 (UTC)

Yes green. Every hail storm i've ever seen has been pre-empted by green clouds. That's how we avert much of the damage. It's highly predictable. Cars go under car ports etc. Factoid Killer 22:24, 31 March 2006 (UTC)

And now it's sourced. By the way, where is here? Factoid Killer 22:50, 31 March 2006 (UTC)

Just some further suggested reading for you... Anecdotal evidence Factoid Killer 23:15, 31 March 2006 (UTC)

Ah it all makes sense now. This user has the longest history of vandalism an trolling i've ever come across. Factoid Killer 00:26, 1 April 2006 (UTC)

Removed comments about green clouds. The green coloration makes no indication of the contents, severity, or potential precipitation of a cloud. It is only caused by the fact that heavy concentrations of moisture in clouds make them blue, and light from the sun as it sets becomes more yellow-red. The resulting light refraction is green. Source here: http://weather.ou.edu/~fgallag/research/grntrw/sld001.htm 71.199.72.85 (talk) —Preceding undated comment added 11:19, 21 May 2010 (UTC).

Changes made April 14 2006[edit]

I changed the statement about hail occuring in non-thunderstorms. Hail by definition occurs in convective clouds, so what was being described is not hail. In winter hail is rare because intense thunderstorms are relatively rare. In winter convective events (like thunder snows), supercooled water droplets are relatively infrequent and hail cannot grow.

Also, I know that factoid killer says that hail is much more common in tropical and subtropical regions but that is false. Hail is most common in midlatitudes during early summer. While, it is true that hail is rare across europe, it is extremely common across the Northern & Central US and southern Canada, and most of midlatitude asia (china, all the former soviet republics, india, etc..), as well as many midlatitude mountains such as the Himalayas, Rockies, Alps, etc ... In lowland Europe hail is supressed mainly because there is a lack of dry air entrainment (as is common over the great plains of the US and in asia), and most thunderstorms there are mechanically forced by strong disturbances and much less so by intense bouyant instabilities. For intense storms you need both strong disturbances which lower the heights (making it colder aloft) and intense warming of the surface (at least 25C and more like 30 to 35C). Europe doesn't get that hot during stormy weather.

Hail in the subtropics occurs mainly in regions adjacent to continental climates in midlatitudes and mainly during spring before upper level ridging gets too strong/upper levels get too moist. Hail in the tropics is pretty rare (see south Florida, the only region with a truly tropical climate in the US and yet the most thunderstorms per year.)


  • Firstly, I'm more than happy to be disproven if it's going to benefit the article and perhaps improve my understanding. You certainly sound like you know what you're talking about but I have to say, some of what you've stated here doesn't comply with my own experiences growing up in the hail prone, subtropical, region of South East Queensland, Australia. I've no intention of reverting your changes based on this anecdotal evidence, however, can I ask that you cite some sources for the new information you've provided?
  • Secondly, Meteorologically, it may be the case that the ice that falls from the sky over London is actually not considered to be hail, but it is commonly referred to as hail by the general public. I believe a distinction should be made. Many people are going to be coming to this article with only an understanding of that concept of hail. British people tend to find it very difficult to believe when I tell them Brisbane gets hail in the middle of summer when the temperature outside is 35 degrees plus. Factoid Killer 10:51, 15 April 2006 (UTC)
  • Finally, can you please sign your comments by leaving four tilds (~ - that's a tild) at the end of your comment. Factoid Killer 10:51, 15 April 2006 (UTC)
Australia does get much more hail than the UK, but the UK is not the ne plus ultra of temperate climates. Just because something isn't common in London doesn't mean it isn't common in temperate areas. Come to nice temperate (on a good day) Calgary - I haven't seen a year since 1981 that didn't have 15 or more hailstorms, and over $40 million in hailstorm damage from at least one storm.
According to the weather specialists at Environment Canada, hailstorms are more common in areas close to places where thunderstorms form, such as areas of high temperature and humidity and the lee side of high mountains. If the storm was formed more than 75 or so km away the hail will likely have already fallen. This is why both subtropical humid areas and places like Calgary have numerous major hailstorms. --Charlene.fic 22:39, 19 October 2006 (UTC)

how does hail form updrafts within thunderstoms push rain high into the cloud where every cold air freezes it. once is frozen it starts to fall but gets caught in another strong updrafts where it gathers more moisture and more moister

Hail[edit]

There is no temperature requirement for hail. Simply hail must fall from a convective cloud. Over the British Isles, convection occurs frequently when surface temps are as low as 10C. When ice falls from nonconvective clouds it is NOT hail. That is the only distinction to be made.

http://amsglossary.allenpress.com/glossary/search?id=hail1

--Dba5 20:07, 7 September 2006 (UTC)

Frozen Precipitation[edit]

Not all frozen precitation is hail or snow, Ice Pellets are often called Hail, Snow Grains are also called Hail, they are not Hail, whatever the weather presenter on the tv may call it. I've heard the tv say we had 'sleet' falling during an early winter storm, there is no such thing as 'sleet' it is just a locally accepted term in Canada to describe Rain and Snow falling at the same time. It is not Meteorologically correct, just as your tv weather presenters are calling Ice Pellets and Snow Grains 'Hail' does not make it correct, only a locally accepted term, Met slang. Remember, most of the people you see tv doing weather are not Meteorologists in any shape or form, they are weather presenters, trained in how to turn Met jargon into everyday language. I have Observed and Reported the weather in a half dozen countries on 3 continents (each has slightly different ways of doing things) 2 different oceans (again diferent than land reporting) and given weather briefings to everyone from pre-schoolers to scientists . . . and 'soft hail' is not Meteorology, it is Met slang, and belongs on a different page with 'sleet' and 'snard' and all other local words. Dcwinds 05:41, 14 September 2006 (UTC)

Sleet is a recognized American term used by the NWS and by various university meteorological departments (such as UIUC) for frozen raindrops. I'm in Canada and I've never heard it used to refer to a mix of rain and snow. Neither have anything to do with hail. --Charlene.fic 22:44, 19 October 2006 (UTC)

Changed spelling on Labor Day. I know the world version but on Sept. 7th this was a United States holiday.

'Hail' vs. 'Sleet' vs. 'Ice Pellets'[edit]

I have just completed my B.S. in Meteorology, and one of the points that my professors really drove home over, and over, again is the difference between hail and sleet.

The American standard definitions, based on how my professors and textbooks repeatedly defined them, and how the National Weather Service uses them are as follows:

  • 'Hail' is defined as ice that forms on condensation nuclei in the updraft of a severe thunderstorm
  • The phrase 'Ice Pellets' is an internationally generic description for precipitation that leaves the cloud in liquid form, and then freezes before reaching the ground (as opposed to snow and hail, which solidify while still in the cloud)
    • The term 'Sleet' is the American term for ice pellets, similar to how 'Hurricane' is the American word for a tropical cyclone (as opposed to a typhoon)
  • 'Freezing Rain' refers to any precipitation that reaches the surface in liquid form and then freezes on the surface.

A common pet peeve of meteorologists and other members of the American scientific community is that the general American populous does not distinguish between these forms of precipitation, nor do they know that there is a distinction to be made.

Most Americans erroneously refer to all forms of frozen precipitation that are not snow as 'Hail.'

This problem is particularly prevalent in areas where either severe thunderstorms aren't as common, and thus neither is hail, or winter weather is not as common, and thus sleet is not as common. If people don't usually see both types, they are less likely to see or to understand the distinction. - Dayjes 00:37, 2 August 2007 (UTC)

Pretty much correct; and important points to make. I'd clarify that, for hail, it's condensation nucleii, i.e. initially liquid precip that then freezes in the cloud. Also, the storm doesn't have to be severe, since that has a specific definition (criteria) in the US, Canada, Australia, and perhaps other areas. For a storm to be severe, hail is one of the criterion, but it must of some size (e.g. 2 cm), and not all hail is severe.
So a thunderstorm can produce hail, which is not severe and thus not a severe thunderstorm (based on the hail criteria, which begs the question: what about storms that are severe for other criteria but not hail), but it's still hail. It does take an updraft of some strength to produce true hail; and some buoyancy, not merely dynamic or isentropic lift, so there is a point to be made about intensity, but to avoid confusion the term severe should be retained for thunderstorms matching decreed criteria.
More headaches can be made of nonconvective events where liquid precip freezes in cloud; or for the smörgåsbord of distinct cool season types that all fall under the ice pellets category. Evolauxia (talk) 02:59, 16 April 2008 (UTC)

cleanup[edit]

This article needs alot of cleanup, with afew more inline references thrown in. I think that it also needs some expansion. Juliancolton 14:55, 8 November 2007 (UTC)

The formation section is properly referenced, mainly coupled with the precipitation (meteorology) peer review and possible FAC run. Thegreatdr (talk) 19:44, 15 July 2009 (UTC)

I found that the discussion on the saturation vapor pressure over ice being slightly less than that over water confusing. I don't see how this difference in saturation pressures favors hail over rain. Unfortunately, I am no expert and am still confused as to how this works. 63.230.1.79 (talk) 06:28, 25 December 2007 (UTC)

SHGS[edit]

Re the piped link SHGS - [[Snow pellets|SHGS]]: "SHGS" is not explained. --Chriswaterguy talk 23:16, 28 February 2008 (UTC)

Size of Hail[edit]

Does anyone have a definitive source on the size of hail? The current opening paragraph makes it unclear whether the minimum size for hail is 5 mm or 1 mm: "Hailstones on Earth...measure between 5 and 50 millimeters in diameter...Hail is only produced by cumulonimbi (thunderclouds)...and is composed of transparent ice or alternating layers of transparent and translucent ice at least 1 mm thick. Small hailstones are less than 5 mm in diameter, and are reported as SHGS." Jerdwyer (talk) 20:58, 19 April 2008 (UTC)

Sourcing for those statements is dealt with. Thegreatdr (talk) 19:21, 16 July 2009 (UTC)
Does this article text mean much?
Stones just larger than golf ball-sized are one of the most frequently reported hail sizes.
The point is that this is only for "reported" hail.
The article implies that hail below 5mm cannot be "reported" in the METAR system. And I suspect that hail of 6mm would often go unreported when it occurred. The statement in the article may be accurate, but the article text also needs to be meaningful. At the least I would recommend a clarification of context.
—DIV (138.194.12.32 (talk) 04:22, 6 October 2009 (UTC))

Gallery removed[edit]

I've removed the gallery since all of the photos are located at in commons which in the end now makes the article more reader friendly. Bidgee (talk) 03:36, 31 May 2008 (UTC)

I removed the gallery again, but inserted a few of its images throughout the article, to comply with MoS. Thegreatdr (talk) 19:22, 16 July 2009 (UTC)

Hail and aircraft[edit]

What happens when an aircraft enters in a cloud full of hail?Is it damaged or even downed?Agre22 (talk) 10:45, 24 December 2008 (UTC)agre22

hailstorms[edit]

The way hail storms get so powerful is from rain,snow and sleet.there is one reason they never had alot of details about them and hailstorms are many things but they dont stink they can achulay help alot people in different ways.like if you wanted to stay with your family you could stay home because of a very bad storm out.hailstorms have alot of details like they have character and snow like sushi rice stuck together and they have skills and alot of history that everybody could learn about. —Preceding unsigned comment added by 24.62.207.36 (talk) 16:18, 19 January 2009 (UTC)

US Bias[edit]

There was a US bias tag on the weather radar section, since it primarily talked about NWS and NEXRAD. I've re-worded it to only refer to weather radar in general, but I did retain the info on NEXRAD (along with the tag). If the tag is no longer appropriate, please remove it, I don't consider myself familiar enough with Wikipedia rules on this topic.

Jimgeorge (talk) 19:57, 7 June 2009 (UTC)

Removed the offending line and tag. Thegreatdr (talk) 19:23, 16 July 2009 (UTC)

Megacryometeor[edit]

While it has no place in this article, apparently large chunks of ice, known as Megacryometeors, have been falling from clear skies occasionally worldwide. While people swear it has nothing to do with the emptying of toilets from planes aloft, some of apparently taking this phenomenon seriously. Thegreatdr (talk) 15:02, 28 August 2009 (UTC)

Terminal Velocity[edit]

I'm confused where the numbers for terminal velocity come from (2011/04/10) which state that a 1 cm hailstone falls at 9 m/s and a 8 cm stone at 48 m/s.

The equation for terminal velocity is

\sqrt\frac{2mg}{\rho_A A C_d}

using

m=V\rho_H

gives

\sqrt\frac{4 d g\rho_H}{3\rho_A C_d}
=\sqrt{d}\sqrt\frac{4 g\rho_H}{3\rho_A C_d}

Or if you account for buoyancy effects the equation is

\sqrt{d}\sqrt{\frac{4 g}{3 C_d} \left( \frac{\rho_H - \rho_A}{\rho_A} \right)}

In either case, terminal velocity is directly proportional to the square root of the diameter. So if a 1 cm stone falls at 9 m/s then an 8 cm stone should fall at 9 \sqrt{\left( 8\right)} = 25.456 m/s not 48 which is incredibly too high.

If no one responds, I will attempt to come up with legitimate numbers and will list the variable values I use. — Preceding unsigned comment added by TommySzalapski (talkcontribs) 16:10, 11 April 2011 (UTC)