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Good articleRain has been listed as one of the Natural sciences good articles under the good article criteria. If you can improve it further, please do so. If it no longer meets these criteria, you can reassess it.
Article milestones
DateProcessResult
February 1, 2010Good article nomineeListed
February 19, 2010Peer reviewReviewed
Current status: Good article


Incorrect probabilities for return periods

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The article states (under the heading Intensity) that a 1 in 10, or 1 in 100 year flood is 50% likely to occur over 10 or 100 years respectively. This is not true. The probability is approximately 65% and 63% respectively.

This can be calculated as 1 minus the probability of no flood. The probability of no flood is a binomial distribution with x=0, n (the number of years) and p (the probability of occurrence in a single year (p=1/n)).

To check this out quickly, use this calculator which will do the calc for you https://www.weather.gov/epz/wxcalc_floodperiod.

Please replace 50% with 65 and 63% for 1 in 10 and 1 in 100 year floods.

Cheers, Fraser 90.248.13.248 (talk) 10:42, 28 October 2021 (UTC)[reply]

I've reverted it back to this version (the last correct version December 2016) rather than use the calculator you linked. That version is more easily understandable and directly verified by the sources (as well as being correct). Thanks for bringing it to our attention, it has been wrong since January 2017! SpinningSpark 14:40, 28 October 2021 (UTC)[reply]
I agree with the maths but I think the text has the logic backwards. The defn of a 100-y flood is (according to source) that it has a 1% prob in a given year; from this you can deduce that it is likely to occur ~1/century William M. Connolley (talk) 15:37, 28 October 2021 (UTC)[reply]
I don't think that's the definition at all, nor does the source say it is the definition. The definition of a 10-y flood is that it has an average recurrence of 10 years. Here's a source that says that. The definition is the recurrence interval, the yearly probability is the inverse of that. Here's a source that says the probability is the inverse of the interval. Really, the definition is in the name, but the two are so directly related that they are equivalent statements. SpinningSpark 16:22, 28 October 2021 (UTC)[reply]
I was relying on the ref we use in the article, http://bcn.boulder.co.us/basin/watershed/flood.html, which says The terms "10 year", "50 year", "100 year" and "500 year" floods are used to describe the estimated probability of a flood event happening in any given year... A 10 year flood has a 10 percent probability of occurring in any given year, a 50 year event a 2% probabaility, a 100 year event a 1% probability, and a 500 year event a .2% probability. While unlikely, it is possible to have two 100 or even 500 year floods within years or months of each other. William M. Connolley (talk) 16:57, 28 October 2021 (UTC)[reply]
Thinking more slowly: our Return period article says The theoretical return period between occurrences is the inverse of the average frequency of occurrence. For example, a 10-year flood has a 1/10 = 0.1 or 10% chance of being exceeded in any one year and a 50-year flood has a 0.02 or 2% chance of being exceeded in any one year. - which is the defn I picked. But it also says A return period, also known as a recurrence interval or repeat interval, is an average time or an estimated average time between events.... And having thought about it, I think (but am not fully confident) that those two are equivalent, in the long run. However, they are not equivalent to The term 1 in 10 year storm describes a rainfall event which is rare and is only likely to occur once every 10 years which is the text we had before I changed it; at least in part because the "only likely" is ill-defined and so near meaningless William M. Connolley (talk) 21:13, 28 October 2021 (UTC)[reply]
"...used to describe the estimated probability" is not the same as "...defined as the estimated probability." You are right about the "only likely" phrase though. SpinningSpark 21:57, 28 October 2021 (UTC)[reply]
Furthermore, the first source in that section makes it clear that the probability is only the inverse of return period under a specific condition (that the probability is assumed to be the same in every period). SpinningSpark 23:04, 29 October 2021 (UTC)[reply]

@Velella: I think this was your edit. SpinningSpark 14:42, 28 October 2021 (UTC)[reply]

Removed section: Outside Earth

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I have removed this section on "Outside Earth" because I don't think it fits here. The article is clearly about water droplets and not about rain of other things. This section could perhaps be moved to another article where it may fit better:

Rainfalls of diamonds have been suggested to occur on the gas giant planets, Jupiter and Saturn,[1] as well as on the ice giant planets, Uranus and Neptune.[2] There is likely to be rain of various compositions in the upper atmospheres of the gas giants, as well as precipitation of liquid neon in the deep atmospheres.[3][4] On Titan, Saturn's largest natural satellite, infrequent methane rain is thought to carve the moon's numerous surface channels.[5] On Venus, sulfuric acid virga evaporates 25 km (16 mi) from the surface.[6] Extrasolar planet OGLE-TR-56b in the constellation Sagittarius is hypothesized to have iron rain.[7] Accordingly, research carried out by the European Southern Observatory shows that WASP-76b can produce showers of burning liquid iron droplets once temperature decreases during the planet's night hours.[8] There is evidence from samples of basalt brought back by the Apollo missions that the Moon has been subject to lava rain.[9] EMsmile (talk) 08:19, 5 May 2023 (UTC)[reply]

References

  1. ^ Kramer, Miriam (9 October 2013). "Diamond Rain May Fill Skies of Jupiter and Saturn". Space.com. Archived from the original on 27 August 2017. Retrieved 27 August 2017.
  2. ^ Kaplan, Sarah (25 August 2017). "It rains solid diamonds on Uranus and Neptune". Washington Post. Archived from the original on 27 August 2017. Retrieved 27 August 2017.
  3. ^ Paul Mahaffy. "Highlights of the Galileo Probe Mass Spectrometer Investigation". NASA Goddard Space Flight Center, Atmospheric Experiments Laboratory. Archived from the original on 23 June 2012. Retrieved 6 June 2007.
  4. ^ Katharina Lodders (2004). "Jupiter Formed with More Tar than Ice". The Astrophysical Journal. 611 (1): 587–597. Bibcode:2004ApJ...611..587L. doi:10.1086/421970.
  5. ^ Emily Lakdawalla (21 January 2004). "Titan: Arizona in an Icebox?". The Planetary Society. Archived from the original on 24 January 2005. Retrieved 28 March 2005.
  6. ^ Paul Rincon (7 November 2005). "Planet Venus: Earth's 'evil twin'". BBC News. Archived from the original on 18 July 2009. Retrieved 25 January 2010.
  7. ^ Harvard University and Smithsonian Institution (8 January 2003). "New World of Iron Rain". Astrobiology Magazine. Archived from the original on 10 January 2010. Retrieved 25 January 2010.
  8. ^ "On a Faraway Planet, it's Cloudy With a Chance of Liquid Iron Rain". NBC News. Retrieved 4 May 2020.
  9. ^ Taylor, G. Jeffrey, "Finding distant chips from distant maria", pp. 8–9, Planetary Science Research Discoveries, 30 April 2006.

EMsmile (talk) 08:19, 5 May 2023 (UTC)[reply]

Good catch. We haven't observed any raining phenomena directly. Maybe we should add back info about Titan though, since that's the only body in the solar system other than the Earth that has liquid on the surface. CactiStaccingCrane (talk) 04:06, 27 May 2023 (UTC)[reply]
I don't think we need info about Titan here. It's not what people expect to see when they search for rain. There would be other articles about the universe that could contain that. See also Rain (disambiguation). Interestingly, the first sentence there says Rain is a type of precipitation in which liquid drops of water fall toward the surface of the earth.. Is this a better first sentence than our first sentence which is currently Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity.? EMsmile (talk) 21:13, 13 June 2023 (UTC)[reply]

"Euphemism"

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In Rain#Intensity, the article says

Euphemisms for a heavy or violent rain include gully washer, trash-mover and toad-strangler.

Those are not really euphemisms;there's nothing offensive about a term like "heavy rain". But what should we call them - or should we just delete them? Nø (talk) 10:09, 19 August 2023 (UTC)[reply]

Fixed Vsmith (talk) 15:06, 19 August 2023 (UTC)[reply]

Article review

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It has been a while since this was reviewed, so I took a look and noticed the following:

  • There are lots of uncited statements, including entire sections.
  • There's an "expansion needed" banner on top of the "Pollution and composition" section.

Should this article go to WP:GAR? Z1720 (talk) 23:41, 27 May 2025 (UTC)[reply]

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