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134 votes
Accepted

How can a storm drop 40 inches (1 metre) of rain?

You were right to question whether the atmosphere really held that much water. It comes nowhere close! We use precipitable water to track this, which is the measure of all moisture in the entire ...
JeopardyTempest's user avatar
51 votes

What does a mm of rain mean?

It's confusing to measure liquid in units of length instead of volume, isn't it? Here's how it works. "One millimeter of rain" is actually one cubic millimeter per square millimeter. On average, over ...
jeffB's user avatar
  • 798
25 votes

How can a storm drop 40 inches (1 metre) of rain?

I invite correction if I missed any details, the column of air above you, at any one time, at 100% humidity can hold maybe 3-6 inches (75-150 mm) of water depending on temperature and it's likey to ...
userLTK's user avatar
  • 5,857
23 votes

How is rainfall measured when the news speaks of "two inches of rain"

A wheelbarrow is usually considerably wider at the top than at the bottom, so the accumulated water at the bottom will likely be deeper than what actually fell. However, rainfall can also have ...
damp_civil's user avatar
22 votes

What does a mm of rain mean?

It is the amount of rain that it takes to cover the ground X milimeters deep. It is normally measured in 24 hours and is measured each morning at a fixed time like 0900. But now the measurements are ...
trond hansen's user avatar
  • 1,878
20 votes

How is rainfall measured when the news speaks of "two inches of rain"

Weather stations measure the depth of rain that falls over a small, set area by setting an open topped cylinder of precise diameter in the open at a standard height above the ground and measuring how ...
Ken Fabian's user avatar
  • 2,120
19 votes

What does a mm of rain mean?

Does it mean that 3mm per square meter was experienced in a specific area, or does it mean that the total amount of rain had a volume such that if it was spread over all of Hong Kong the height ...
JeopardyTempest's user avatar
17 votes

Ways to make a "How hard is it raining?" detector for personal use?

If you're open to a more mechanical solution, I'd suggest building a "tipping bucket rain gauge", best explained by a picture (source: https://www.researchgate.net/figure/Sideview-of-tipping-...
Max Klein's user avatar
  • 271
14 votes

Ways to make a "How hard is it raining?" detector for personal use?

Upon reading the question my first thought was, please define what is meant by "how hard is it raining?". My initial tangent thought was "what about the impact energy of the rain" -...
Fred's user avatar
  • 24.7k
13 votes

How can a storm drop 40 inches (1 metre) of rain?

Harvey is almost stationary and is rotating new gulf moisture up the "dirty" side (east of the center). I am outside the main path and have 10+ inches (250 mm) in 30 hours (emptied the rain gauge ...
blacksmith37's user avatar
  • 1,043
13 votes

Ways to make a "How hard is it raining?" detector for personal use?

One way to do that is to estimate how much water is changing. If you can ignore the spill over, then that is approximately how much the puddle is changing. Another idea you can use is to measure the ...
BarocliniCplusplus's user avatar
13 votes

Ways to make a "How hard is it raining?" detector for personal use?

It's not perfect, but a simple solution to the issue of a puddle building up on the resistance plate is to tilt the plate a bit, so that instead of the water building up on the plate it runs off. Your ...
C_Elegans's user avatar
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11 votes
Accepted

How do rivers last so long in dry weather?

The rivers are generally fed by water that percolated into the ground, it takes longer for that water to work its way down to the stream so the streams and rivers keep flowing long after the initial ...
John's user avatar
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10 votes

What does a mm of rain mean?

Given any container with straight sides, 3 millimeters of rainfall will fill up that container to 3 millimeters in depth. The size of the container does not affect this. It holds whether the ...
thomasrutter's user avatar
8 votes
Accepted

Could a reported rainfall pH of 3.1 actually be realistic?

A quick literature search seems to confirm Gordons estimation, even at the scale of a whole bucket: [T]he annual mean pH, based upon samples collected weekly during 1970-1971 and weighted ...
wienein's user avatar
  • 466
8 votes

Why is northern Australia unsuitable for agriculture?

Erratic Climate Lets take Broome, Australia as our example. Broome gets 615mm of rain a year (24 inches), including 58/182/180/102mm in Dec through March. Coupled with average highs in the low 90s, ...
kingledion's user avatar
  • 3,376
8 votes

Why is the eastern United States green if the wind moves from west to east?

Why is the eastern United States green if the wind moves from west to east? The winds don't move straight from west to east. Oftentimes they move from the southwest to the northeast (and sometimes ...
David Hammen's user avatar
  • 23.7k
8 votes

How is rainfall measured when the news speaks of "two inches of rain"

In addition to what others have mentioned, sometimes measurements are simply wrong, in particular where measurements are automated. Some weeks ago, two weather stations in Germany reported over 60 mm ...
gerrit's user avatar
  • 11.7k
7 votes

Could a reported rainfall pH of 3.1 actually be realistic?

Raindrops gain a small amount of acidity as they fall through carbon dioxide in the air, but that's not what this question is about. Raindrops commonly start off as ice crystals which have to nucleate ...
Gordon Stanger's user avatar
7 votes
Accepted

Why is thunder and lightning rare, even though it rains frequently?

Rain in a climate such as Ireland is most often stratiform. That is, it is created when moist air is lifted by a front, or by divergence in the upper troposphere. Thunderstorms involve buoyant air, ...
jakewx's user avatar
  • 96
7 votes

How to recharge ground water directly from river water

The solution you are looking for is called "artificial recharge of aquifers" or "managed underground storage of recoverable water", among several other names. Several different ...
tanius's user avatar
  • 171
6 votes
Accepted

The sun sometimes appears pure white after rainfall, how can this be explained?

When it rains the raindrops nucleate around aerosol particles of salt, dust, clay, soot, dimethyl sulphide, etc. In addition a falling raindrop may pick up any particulate matter that may be in its ...
Gordon Stanger's user avatar
6 votes

Where can I find the record for the heaviest single-day rainfall ever recorded on any date at a specific location?

Sounds like your question, like most questions about historical data, might be a little challenging to find the right source, as it often is around the world. But seeing you said Atlanta brightened ...
JeopardyTempest's user avatar
6 votes

How can a storm drop 40 inches (1 metre) of rain?

The atmosphere can "hold" only maximum 75mm worth of precipitation at any given locality, this is true. However, this particular hurricane Harvey was a very slowly moving structure. The vortex would ...
Ale..chenski's user avatar
6 votes

Is there a consensus on the "heaviness" of rain?

If there was a worldwide standard, then WMO would have imposed it to its members. Here are the definitions in the American (NOAA/NWS) standard (summarized at NJWeatherScan, initially from manuals like ...
DanielC's user avatar
  • 171
6 votes

Ways to make a "How hard is it raining?" detector for personal use?

I would approach this by counting pings on a plate with an attached piezo or microphone. The amplitude of the ping will give the volume of the drop and the number of pings the drop quantity. This is a ...
user2825367's user avatar
6 votes

Ways to make a "How hard is it raining?" detector for personal use?

A 'video disdrometer' is a device for characterizing raindrop size distributions. Professional versions (e.g A 1D distrometer) can use a video camera to image the shadow cast by water droplets moving ...
Andy M's user avatar
  • 2,091
6 votes

How is rainfall measured when the news speaks of "two inches of rain"

Properly designed rain gauges can give accurate results for a given location or point in space, but the problem is that it's hard to have enough of them packed densely enough in an area to give the ...
anjama's user avatar
  • 161
5 votes
Accepted

How to determine constant $C$ in $p(x) = Cx^{-D}$?

There are two solutions using the least square method for calculating $C$ and $D$. Both methods yield different results for your constants. There is no correct method. Method of least Squares We ...
daniel.heydebreck's user avatar
5 votes

How do rivers last so long in dry weather?

A river's primary of source of water is precipitation, surface water run off, and shallow groundwater discharge within the drainage basin the river is located. The size of the drainage basin really ...
Earth Science Expatriate's user avatar

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