# How heavy would it have to rain to flood the Earth in 40 days? **URL:** \ **Category:** Factual Questions\ **Created:** [May 25, 2019, 6:24am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494 "2019-05-25T06:24:19Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Flyer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/flyer/32/7298_2.png) [@Flyer](https://boards.straightdope.com/u/Flyer)\ **Post date:** [May 25, 2019, 2:51pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/21 "2019-05-25T14:51:04Z")
There are several mistaken assumptions in the OP’s question. One, as **kanicbird** pointed out, is ignoring other sources of water. Another is ignoring changes in world-wide climate. Yet another is assuming that the height of the highest mountain today is similar to what it was at the time in question. It’s easy to calculate what the answer would be in today’s world. Whether that answer bears even a passing resemblance to the correct answer at the time that the earth was actually flooded is another matter entirely. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [May 25, 2019, 2:51pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/22 "2019-05-25T14:51:29Z")
[Ark Encounter LLC Files Lawsuit After Heavy Rains Damage Property](https://lex18.com/news/covering-kentucky/2019/05/24/ark-encounter-llc-files-lawsuit-after-heavy-rains-damage-property/) > [@](#): > > (LEX 18) – The Ark may have been constructed to withstand 40 days and 40 nights of flooding, but Northern Kentucky’s Ark Encounter property did not fare as well as Noah’s original construction when rains hit the area. > > Court documents filed in District Court show that the owners of the Ark Encounter in Northern Kentucky have filed a suit against their insurance company after flood and storm damage. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [May 25, 2019, 3:10pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/23 "2019-05-25T15:10:37Z")
> [@Flyer](#): > > There are several mistaken assumptions in the OP’s question. One, as **kanicbird** pointed out, is ignoring other sources of water. > > Another is ignoring changes in world-wide climate. > > Yet another is assuming that the height of the highest mountain today is similar to what it was at the time in question. > > It’s easy to calculate what the answer would be in today’s world. Whether that answer bears even a passing resemblance to the correct answer at the time that the earth was actually flooded is another matter entirely. Anatomically modern homo sapiens have been around either 200,000 years or 6,000 years, depending on your sources, but either way, I don’t think the earth has changed that much over that time frame. I don’t it’s very long geologically speaking. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [May 25, 2019, 3:24pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/24 "2019-05-25T15:24:03Z")
Yes, if you ignore everything we know about geology, it’s possible to believe that all the earth’s high mountains sprang up in the last few thousand years. And if you ignore everything we know about physics, it’s possible to believe that vast reservoirs of water under the earth suddenly emerged from the ground, leaving vast empty chasms that somehow disappeared, along with the water. And if you ignore the first sentence of the OP, it’s possible to believe that Flyer’s response was relevant to this thread. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 25, 2019, 4:05pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/25 "2019-05-25T16:05:50Z")
> [@panache45](#): > > And what the hell kind of clouds could supply the planet with that much rain? Magic clouds. No natural process could provide that. First of all, consider the solar energy needed to evaporate that much water. Once clouds form and blanket the Earth, the sun can no longer reach the ocean’s surface to evaporate more. And of course, once the atmosphere reaches 100% humidity no more can evaporate. > [@Flyer](#): > > Yet another is assuming that the height of the highest mountain today is similar to what it was at the time in question. > > It’s easy to calculate what the answer would be in today’s world. Whether that answer bears even a passing resemblance to the correct answer at the time that the earth was actually flooded is another matter entirely. According to all geological evidence, the last time the surface of Earth was almost entirely under water was about 2.5 billion years ago. But that wouldn’t be particularly catastrophic, since all life at the time was aquatic and consisted mostly of bacteria. ---
**Author:** ![kaylasdad99](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kaylasdad99/32/3398_2.png) [@kaylasdad99](https://boards.straightdope.com/u/kaylasdad99)\ **Post date:** [May 25, 2019, 4:42pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/26 "2019-05-25T16:42:52Z")
> [@TriPolar](#): > > Yes. It’s only accumulating at 1/10 of an inch per second. That means a drop with **a volume of 1/10 of a square inch** has to hit the ground or water surface per second. If my math is correct (which is highly unlikely), assuming spherical drops, that’s somewhere around a .31 inch diameter drop per second. Plenty of space in between them. Nitpick: 0.1 in[sup]2[/sup] is an _area_, not a _volume_. Actually, I don’t even need to be numerically specific. _Any_ measurement expressed in square inches is an area and not a volume. > [@Flyer](#): > > There are several mistaken assumptions in the OP’s question. One, as **kanicbird** pointed out, is ignoring other sources of water. > > Another is ignoring changes in world-wide climate. > > Yet another is assuming that the height of the highest mountain today is similar to what it was at the time in question. > > It’s easy to calculate what the answer would be in today’s world. Whether that answer bears even a passing resemblance to the correct answer **at the time that the earth was actually flooded** is another matter entirely. Ummm. Do you believe that the planet _was_ ACTUALLY flooded, or are you just being extra diligent about not fighting the hypothetical, here? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 25, 2019, 6:26pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/27 "2019-05-25T18:26:42Z")
> [@kaylasdad99](#): > > Nitpick: 0.1 in[sup]2[/sup] is an _area_, not a _volume_. > > Actually, I don’t even need to be numerically specific. _Any_ measurement expressed in square inches is an area and not a volume. Yes, whatever the volume is, I meant cubic inches. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [May 25, 2019, 6:49pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/28 "2019-05-25T18:49:30Z")
> [@TriPolar](#): > > Yes, whatever the volume is, I meant cubic inches. Of course, volumes may have been measured in square inches at the time the earth actually flooded. There’s just no way to know. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [May 25, 2019, 7:00pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/29 "2019-05-25T19:00:03Z")
In terms of sticking with just one miracle, the rain, we can ignore the percentage added by water spewing forth from underground. The water coming from below would have resulted in the ground above them sinking to replace the water (and magically leaving no sign of such collapses or where the underground water came from in the first place). This would have had very little to no affect on overall water level over the vast majority of the planet. Keep in mind that 71% of the planet is covered by water. Water coming from below that water does nothing at all as the seabed sinks to fill in. Ditto areas near coasts, etc. for the most part. You’d have to theorize that most of the land was much, much higher than it was today. There would have to have been amazing waterfalls on the Mississippi which would have left noticeable affects. And speaking of Everest, if it was significantly higher with magic water reservoirs under it and it sank to its present height during the flood, then you’ll have to explain how such a massive mountain stayed so intact as so much material under it flowed away in such a tiny period of time. (Never mind how it got there, stayed there, didn’t boil away, etc.) And if some parts of Asia had a lot of water under it and not other ones, the differential settling would also be easily seen. And on and on. No, vast caverns of water coming up don’t affect the overall calculation. Note in doing a precise calculation: “The waters rose and covered the mountains to a depth of more than fifteen cubits.” So add a few more feet, at least. (How the writer knew it was at least fifteen cubits is Yet Another Mystery.) And then there’s the question of where the water went. But I guess not this thread. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [May 25, 2019, 7:01pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/30 "2019-05-25T19:01:00Z")
> [@Riemann](#): > > Of course, volumes may have been measured in square inches at the time the earth actually flooded. There’s just no way to know. True, a lot of things were different. After all, pi was equal to 3.0 back then. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 25, 2019, 7:04pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/31 "2019-05-25T19:04:57Z")
> [@Riemann](#): > > Of course, volumes may have been measured in square inches at the time the earth actually flooded. There’s just no way to know. :). Actually I was visualizing the simple rain gauge I have which is a square plastic tube with an opening of 1 square inch at the top. I hadn’t noticed **TokyoBayer** ’s calculation either. Glad it agrees. The calculation is all about covering Mt. Everest because the vast majority of the earth’s surface is already filled with water up to sea level, and most of the rest only a little above that. The real answer is that no matter how hard it rains the water will never exceed sea level by much because there isn’t enough water, and the excess mainly comes from ice melt. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [May 25, 2019, 7:07pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/32 "2019-05-25T19:07:50Z")
> [@ftg](#): > > And then there’s the question of where the water went. I think I know this one. Turned into wine. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [May 25, 2019, 7:08pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/33 "2019-05-25T19:08:23Z")
Especially considering this is GQ, I find it interesting that most posters appear to not have read the OP, or the followup posts by the OP reinforcing the OP. It’s a simple question, and should have a simple answer based on geology, physics, and mathematics. Although it is obvious what the motivation for the question is, the OP did not ask for consideration of extenuating circumstances, an allowance for evaporation, an allowance for the “fountains of the deep” to contribute, an allowance for other supernatural factors or an exploding sun, or a climate change correction to be included. IOW, just answer the fucking question and we can move on! ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 25, 2019, 7:15pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/34 "2019-05-25T19:15:31Z")
> [@TokyoBayer](#): > > This is such an elementary math problem that I wonder if there is another purpose for the question. > > Mt. Everest is 29,029 ft. Divide that by 40 days, 24 hours per day and 60 minute per hour. I get 6” of rain per minute. > > A quick google search shows the record rainfall in one minute is 1.22”. I’ve seen some claims that the mountains did not exist before the flood, so the 60 feet mentioned in the OP would be the number to use. Mountains thrust up after (like the one Noah supposedly landed on) but that’s irrelevant to the calculation. So I stand by 60 feet / 40 days or 18 inches a day or 3/4 inch per hour. Adjusted for seepage and evaporation, of course. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 25, 2019, 7:16pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/35 "2019-05-25T19:16:54Z")
> [@Riemann](#): > > I think I know this one. Turned into wine. _hic_ ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [May 25, 2019, 7:18pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/36 "2019-05-25T19:18:53Z")
> [@Musicat](#): > > Especially considering this is GQ, I find it interesting that most posters appear to not have read the OP, or the followup posts by the OP reinforcing the OP. It’s a simple question, and should have a simple answer based on geology, physics, and mathematics. > > Although it is obvious what the motivation for the question is, the OP did not ask for consideration of extenuating circumstances, an allowance for evaporation, an allowance for the “fountains of the deep” to contribute, an allowance for other supernatural factors or an exploding sun, or a climate change correction to be included. > > IOW, just answer the fucking question and we can move on! We don’t know pre-flood geography, which makes it kind of tough. The existence of oceans is irrelevant, for to have the water level on land raise by 60 feet seal level must also raise by 60 feet. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [May 25, 2019, 7:22pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/37 "2019-05-25T19:22:13Z")
> [@kaylasdad99](#): > > Do you believe that the planet _was_ ACTUALLY flooded, or are you just being extra diligent about not fighting the hypothetical, here? Among many other things, flyer is a Young-Earth Creationist. ---
**Author:** ![Colibri](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/colibri/32/1841_2.png) [@Colibri](https://boards.straightdope.com/u/Colibri)\ **Post date:** [May 25, 2019, 7:23pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/38 "2019-05-25T19:23:55Z")
> [@Musicat](#): > > Especially considering this is GQ, I find it interesting that most posters appear to not have read the OP, or the followup posts by the OP reinforcing the OP. It’s a simple question, and should have a simple answer based on geology, physics, and mathematics. > > Although it is obvious what the motivation for the question is, the OP did not ask for consideration of extenuating circumstances, an allowance for evaporation, an allowance for the “fountains of the deep” to contribute, an allowance for other supernatural factors or an exploding sun, or a climate change correction to be included. > > IOW, just answer the fucking question and we can move on! **Moderating** I find it interesting that you’ve been around a long time without being aware of the rule against junior modding. The basic answer was given in the first few posts. By your standards I should just go ahead and close the thread after that. Once the question has been answered, discussion of related issues is allowed. If this bothers you, you are free to stop reading the thread. Colibri General Questions Moderator ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 25, 2019, 7:29pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/39 "2019-05-25T19:29:36Z")
> [@Musicat](#): > > Especially considering this is GQ, I find it interesting that most posters appear to not have read the OP, or the followup posts by the OP reinforcing the OP. It’s a simple question, and should have a simple answer based on geology, physics, and mathematics. > > Although it is obvious what the motivation for the question is, the OP did not ask for consideration of extenuating circumstances, an allowance for evaporation, an allowance for the “fountains of the deep” to contribute, an allowance for other supernatural factors or an exploding sun, or a climate change correction to be included. > > IOW, just answer the fucking question and we can move on! The OP asked us to cast aside our beliefs. For most people this makes the calculations impossible because they believe in math. It worked for me because I have never believed in math ever since I found out that I could perform the same calculation three times and get four different answers (and often none of them correct according to so called ‘math’). ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [May 25, 2019, 8:22pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/40 "2019-05-25T20:22:02Z")
> [@Voyager](#): > > We don’t know pre-flood geography, which makes it kind of tough. > The existence of oceans is irrelevant, for to have the water level on land raise by 60 feet seal level must also raise by 60 feet. Regarding pre-flood geography, all we need to know to answer the OP is how much land there was roughly 4000 years ago, in order to subtract that from the volume of water needed. We also need to know the oceanic water level at that time. 4000 years in geological terms is insignificant; and the movement of tectonic plates won’t alter the water volume much (move North America to the left or right and it still occupies the same volume of matter). I don’t have the figures or technical knowledge to do the calculation, but it seems to me that the answer can be derived from: (1) calculate the volume of matter needed to make a sphere larger than Everest (2) subtract the volume of matter needed to make a sphere the size of the Earth at sea level (3) subtract the volume of matter represented by the (non-aquatic) continents above sea level. This would give you the volume of water needed for a 40 days/nights deluge. The remaining calculations are academic, to compute the rate of precipitation. Possible confounding factors would be ice volume at the poles and glaciers. [Previous page](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494.md?page=1) [Next page](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494.md?page=3)