# 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:** 3
**Author:** ![Yllaria](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yllaria/32/3452_2.png) [@Yllaria](https://boards.straightdope.com/u/Yllaria)\ **Post date:** [May 25, 2019, 8:32pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/41 "2019-05-25T20:32:02Z")
> [@kanicbird](#): > > From this, it could have been a light sprinkle, as there was a second source of water, even a case for a 3rd source could be made: . . . In Gen 1 God divided the water above and below, it appears that both were being used here, if not 3 sources (underworld, our world, and from the heavens). Gen 2:5 could be said to make rain that 3rd category of water as it was seperate from the division of waters below and above. I’m perfectly happy to let the OP frame the question any way they like, for any reason they like. If he’s talking about the flood with regular folks, regular rain is probably the idea they’ve picked up. Several people have mentioned underground water and modern geology. Kanicbird referred to the bible verses about the divided waters. According to the one comparative religion class I took (yeah, I know - and it’s been awhile, too), the cosmology in the OT (matching Babylonian cosmology) starts with the universe being water. God divides the waters from the waters, making an area for a flat earth. Above the earth is the vault of the heavens, which is keeping back the water. The sun, moon, and stars are either on the vault of the heavens, or just under it. Then there’s air/the winds, then there’s flat land, then there’s the underworld, then there’s the rest of the water that makes up the rest of the universe. > [@](#): > > Genesis 7:11 In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened. That’s a universe of water, albeit a smaller universe than we’re accustomed to. Actual rain would be negligible compared to it. Although depending on the actual language used at the time, any water coming down from above might have to be described as “raining” - that is, using a word that would have been translated as raining. Ooo. This bit is interesting. > [@](#): > > Genesis 7:20 Fifteen cubits upward did the waters prevail; and the mountains were covered. Cubits vary, but are usually about a foot and a half. I have to believe they mean to say that the top of the mountains were covered by at most twenty three feet of water. As to how it went away: > [@](#): > > Genesis 8:1 And God remembered Noah, and every living thing, and all the cattle that was with him in the ark: and God made a wind to pass over the earth, and the waters assuaged; > > 2 The fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained; > > 3 And the waters returned from off the earth continually: and after the end of the hundred and fifty days the waters were abated. Sounds like the bubble in the vault was deliberately drained. Although they may not have wanted to look at that too closely. I’m not sure what the wind was doing. To me it sounds like it was calming the churning of the flood water. ---
**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, 8:43pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/42 "2019-05-25T20:43:24Z")
> [@Musicat](#): > > 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. Given your prior concerns about thread etiquette, it seems surprising that you don’t appear to have read the thread. TokyoBayer already answered the question with a much simpler approach that doesn’t require volume calculations at post #6. It’s straightforward to check if land elevation makes a significant difference. > **[Earth](https://en.wikipedia.org/wiki/Earth)** > > Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust. The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere. Most of Earth's land is at least somewhat humid and c... ~29% of of the surface is land, at a mean elevation of ~2,600 ft amsl, giving a mean evelation for the entire surface of ~750 ft amsl. That’s less than 3% of the height of Everest, so TokyoBayer’s calculation of a rainfall rate of ~6" per minute is still correct to the nearest inch. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [May 25, 2019, 8:46pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/43 "2019-05-25T20:46:21Z")
> [@Yllaria](#): > > Several people have mentioned underground water and modern geology. Kanicbird referred to the bible verses about the divided waters. According to the one comparative religion class I took (yeah, I know - and it’s been awhile, too), the cosmology in the OT (matching Babylonian cosmology) starts with the universe being water. God divides the waters from the waters, making an area for a flat earth. Above the earth is the vault of the heavens, which is keeping back the water. The sun, moon, and stars are either on the vault of the heavens, or just under it. Then there’s air/the winds, then there’s flat land, then there’s the underworld, then there’s the rest of the water that makes up the rest of the universe. You need all that water for the [astrochelonian](https://wiki.lspace.org/mediawiki/Great_A%27Tuin) to swim in. And don’t forget the [elephants](https://wiki.lspace.org/mediawiki/World_Elephant). Everyone always forgets about the elephants. ---
**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, 8:49pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/44 "2019-05-25T20:49:02Z")
> [@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. > [@Musicat](#): > > Regarding pre-flood geography, all we need to know to answer the OP is how much land there was roughly 4000 years ago.. It’s interesting to compare your two posts here. Can you point out where the OP specifies that he’s asking about something happening 4000 years ago? ---
**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 26, 2019, 6:17am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/45 "2019-05-26T06:17:59Z")
> [@Musicat](#): > > 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. Genesis says that the water extended 15 cubits above the highest mountain. Therefore all you need to do, as before, is decide the height of the tallest mountain, add 15 cubits, divide by 40, and you get the rainfall per day. Clearly this is bit high since you don’t account for the volume of the mountains. I understand that if we are using science Everest is the highest, but I don’t think that is an assumption you can make. I’ve also seen people who claim that the post-flood world was all connected, to explain how the kangaroos got to Australia. If you’re responding to a question in a creationist scenario, you kind of have to play by creationist rules. You certainly don’t have to accept them. ---
**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 26, 2019, 6:20am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/46 "2019-05-26T06:20:14Z")
> [@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. They were obviously measured in cubic cubits. 🙂 ---
**Author:** ![TokyoBayer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tokyobayer/32/13989_2.png) [@TokyoBayer](https://boards.straightdope.com/u/TokyoBayer)\ **Post date:** [May 26, 2019, 7:22am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/47 "2019-05-26T07:22:18Z")
> [@Flyer](#): > > Another is ignoring changes in world-wide climate. How does wold-wide climate change affect things? This is a math question. How would that change? Does climate change mean that 1 inch of water is less or more than 1 inch of water then. > [@](#): > > Yet another is assuming that the height of the highest mountain today is similar to what it was at the time in question. It really doesn’t matter. Mr. Ararat is at 16,854 ft. which would made the hourly rainfall 3’ per hour. Scientifically, that’s impossible as well. > [@](#): > > 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. Young Earth Creationism simply requires abandoning science and relies on miracles. Employing miracles which hide all evidence of themselves means that it can’t be debated. > [@Voyager](#): > > 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. If there are real people who are making claims that the mountains did not exist, they are not reading the Bible. > [@Genesis 6](#): > > For forty days the flood kept coming on the earth, and as the waters increased they lifted the ark high above the earth. 18 The waters rose and increased greatly on the earth, and the ark floated on the surface of the water. 19 They rose greatly on the earth, and all the high mountains under the entire heavens were covered. 20 The waters rose and covered the mountains to a depth of more than fifteen cubits. I know the YEC like to torture readings into supporting whatever they want (I grew up LDS, after all), but no, the text says mountains. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [May 26, 2019, 7:22am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/48 "2019-05-26T07:22:37Z")
> [@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! Forget it, Jake, this is the Dope. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [May 26, 2019, 7:25am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/49 "2019-05-26T07:25:11Z")
> [@Riemann](#): > > I think I know this one. Turned into wine. Thats a lot of wine drinkin’. OK smart guy, where did all the pee go? 🙂 ---
**Author:** ![Czarcasm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/czarcasm/32/4050_2.png) [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)\ **Post date:** [May 26, 2019, 10:24am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/50 "2019-05-26T10:24:15Z")
> [@Voyager](#): > > Genesis says that the water extended 15 cubits above the highest mountain. Therefore all you need to do, as before, is decide the height of the tallest mountain, add 15 cubits, divide by 40, and you get the rainfall per day. Clearly this is bit high since you don’t account for the volume of the mountains. > I understand that if we are using science Everest is the highest, but I don’t think that is an assumption you can make. I’ve also seen people who claim that the post-flood world was all connected, to explain how the kangaroos got to Australia. > If you’re responding to a question in a creationist scenario, you kind of have to play by creationist rules. You certainly don’t have to accept them. At no time did I say that this flood took place any time in the past. ---
**Author:** ![RobDog](https://avatars.discourse-cdn.com/v4/letter/r/f07891/32.png) [@RobDog](https://boards.straightdope.com/u/RobDog)\ **Post date:** [May 26, 2019, 10:52am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/51 "2019-05-26T10:52:52Z")
> [@Czarcasm](#): > > At no time did I say that this flood took place any time in the past. You’re absolutely right, you didn’t. So I am curious as to why you mentioned cubits, a measurement which by any reasonable definition hasn’t been in use for a good 200 years. ---
**Author:** ![Folacin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folacin/32/3195_2.png) [@Folacin](https://boards.straightdope.com/u/Folacin)\ **Post date:** [May 26, 2019, 11:55am UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/52 "2019-05-26T11:55:37Z")
> [@Lucas\_Jackson](#): > > Thats a lot of wine drinkin’. OK smart guy, where did all the pee go? > > 🙂 In a toilet/urinal (or sink for the barbarians), duh. ---
**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 26, 2019, 2:18pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/53 "2019-05-26T14:18:49Z")
> [@Czarcasm](#): > > At no time did I say that this flood took place any time in the past. You didn’t have to. I’ve noticed before that you like to be “cute” and try to sneak things in without actually explicitly saying so. Anybody with the slightest knowledge of the world’s religions knows exactly what you’re doing and what you’re referring to. You’ve been around long enough to know that the innocent guise and the “just asking questions” excuse doesn’t cut it around here. ---
**Author:** ![chaidragonfire](https://avatars.discourse-cdn.com/v4/letter/c/97f17d/32.png) [@chaidragonfire](https://boards.straightdope.com/u/chaidragonfire)\ **Post date:** [May 26, 2019, 2:44pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/54 "2019-05-26T14:44:01Z")
My question would be… WHERE would all this excess water come from that would be needed to actually flood an entire planet? There isn’t enough water on this planet to flood it. Even if all the mountains were leveled, you would still have land sticking out from the water. You would need more water than this planet has, in order to flood it. ---
**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 26, 2019, 2:59pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/55 "2019-05-26T14:59:40Z")
> [@Czarcasm](#): > > At no time did I say that this flood took place any time in the past. **Moderating** Let’s not be disingenuous. Your reference to 40 days and 40 cubits obviously refers to a specific flood described in a specific literary source. It’s OK to ask the question as a hypothetical, but I’m sure you already knew that the event described is scientifically impossible, not just on the basis of rainfall but on a dozen other grounds. You can’t ask the question in the way you did and expect people not to bring up other features of the event as described. Colibri General Questions Moderator ---
**Author:** ![Folacin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folacin/32/3195_2.png) [@Folacin](https://boards.straightdope.com/u/Folacin)\ **Post date:** [May 26, 2019, 3:02pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/56 "2019-05-26T15:02:52Z")
> [@chaidragonfire](#): > > My question would be… > > WHERE would all this excess water come from that would be needed to actually flood an entire planet? > > There isn’t enough water on this planet to flood it. Even if all the mountains were leveled, you would still have land sticking out from the water. You would need more water than this planet has, in order to flood it. Rings of Saturn? Isn’t there a lot of ice floating around the solar system? ---
**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 26, 2019, 4:28pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/57 "2019-05-26T16:28:46Z")
> [@chaidragonfire](#): > > My question would be… > > WHERE would all this excess water come from that would be needed to actually flood an entire planet? > > There isn’t enough water on this planet to flood it. Even if all the mountains were leveled, you would still have land sticking out from the water. You would need more water than this planet has, in order to flood it. > [@Folacin](#): > > Rings of Saturn? Isn’t there a lot of ice floating around the solar system? Posts 9 and 41 address this. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [May 26, 2019, 4:55pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/58 "2019-05-26T16:55:41Z")
Subsequent questions. Would the increased precipitation increase continental weathering that would lead to a snowball earth? Would there be slushball oceans? I think that these would affect how long it would take to get the job done. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [May 26, 2019, 5:18pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/59 "2019-05-26T17:18:56Z")
> [@chaidragonfire](#): > > My question would be… > > WHERE would all this excess water come from that would be needed to actually flood an entire planet? > > There isn’t enough water on this planet to flood it. Even if all the mountains were leveled, you would still have land sticking out from the water. You would need more water than this planet has, in order to flood it. That is debatable: [https://www.newscientist.com/article/2130266-early-earth-was-covered-in-a-global-ocean-and-had-no-mountains/](https://www.newscientist.com/article/2130266-early-earth-was-covered-in-a-global-ocean-and-had-no-mountains/). ---
**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 26, 2019, 5:31pm UTC](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494/60 "2019-05-26T17:31:07Z")
> [@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. > [@kaylasdad99](#): > > Ummm. > > Do you believe that the planet _was_ ACTUALLY flooded, or are you just being extra diligent about not fighting the hypothetical, here? > [@Darren\_Garrison](#): > > Among many other things, flyer is a Young-Earth Creationist. o\_o \>\_\< o\_O Oh dear. [Previous page](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494.md?page=2) [Next page](https://boards.straightdope.com/t/how-heavy-would-it-have-to-rain-to-flood-the-earth-in-40-days/834494.md?page=4)