Or, in other and more comprehensible words…how many inches of rain equal how many inches of snow? What’s the ratio* of one to the other?
(Please say that’s the right word. It will make me feel proud for a few moments.) 
Common wisdom says 1" of rain is equivalent to about 10" of snow. On average, it’s probably somewhere around that, but the actual figure really depends on the type of snow, temperature, humidity and various other factors which affect how well the snow packs and such.
And while we’re at it, why is rain measured in inches, not volume? Snow I can see as being measured in inches… but rain?
Can you give an example as to how you would meaningfully measure it in volume? Do you mean like “a pint of rain fell per square foot last night”? If so, it seems to me that your standard rain gauge would have to be modified and complicated.
In all honesty I haven’t really thought it through, and let’s not gloss over the fact that it’s two in the morning, either. 
But it just seems like hey, rain is water, and we generally measure liquids in pints, gallons, quarts, etc… I suppose the difference though is that that’s a measurement of one specific location, and rain has to be measured over a larger area, right?
P.S. To the OP: Ratio–“The relation between two quantities when compared mathematically with one another.” Sounds right to me!
Yeah…think that one through a little more. It’s reported in inches because that’s the meaningful measurement. No matter how large your collection device is in area, whether it’s a square foot or a square meter, the water level will be at the same height.
You won’t get an exact answer to this question. Snow varies quite a bit in density, enough so that scientists in the antarctic are able to see snow ‘rings’ for each year, similar to the rings in the trunk of a tree.
Just here in Minnesota, for example, the cold, dry snow of January is quite different from the heavy, wet snow of March.
Few moments!!! You should live on **this ** one for weeks!!!
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My recollection is that the ratio varies from about 3" or less of snow per inch of rain when the snow is very “wet”, to as much as 12" when the snow is very dry. I think the rule of thumb is about 7" of snow to an inch of rain.
It can vary from day to day, too. We got quite a dry snow last night, but the eerie warmth overnight partially melted and compacted it into the painful-to-shovel mess I woke up to this morning.
Well it is measured by volume as well. For example Texas receives5.3 million acre-feet of rainfall each year.
Did you get any sense of how wet Texas is?
Only if you know how big Texas is. And, of course, only if you have a good enough feel for the numbers.
I am not sure that is a good number. Texas is supposedly 268,601 square miles. Which is 171,904,640 arcres. Which gives .369 inches of rain per year. That is very low. The web says the annual rainfail in the Sahara is more that that say around 1 to 3 depending.
A review of the link, particularly the second page showing a graph of ground water sourcing indicates that only .369 inches of annual rainfall makes it into Texas groundwater. The rest of the Texas rainfall of course would end up into the ocean or evaporate.
I’d like to point out that volume per area is exactly the same thing as height.
I’m not sure if it’s only us (pedantic Germans) or if it applies to all metric systems but we do indeed measure rainfall in volume per area; liters per square meter, to be exact. 1 liter per square meter would equal a height of 1 millimeter. An inch of rain would be roughly 25 l/m².
Rain gauges don’t look any different here; the only thing that needs to be changed is the scale.
And of course, snowfall is measured in height in the weather forecast because snow can vary in density as has been stated before. When meteorologists compile their precipitation charts they melt it down and express it in l/m², though.
I read on Accuweather that it also has to do with wind chill versus how rain converts into snow. I’m trying to look for the article, but I’m not having much luck. I know it’s not an exact science as there are many minute factors that can change it. If I find it, I will post it here.
I believe Atlatanta ABC Affiliate WSB-TV stated yesterday (2/6). that one inch or rain equates to 8 - 10 inches of snow.
- Inches of rain is easier to realate to as the amount per x number of square units of area can be calculated if needed.
- A pint (lets not digress here) per square unit of area is pretty meaningless.
- Now go have your pint!
As flex727 said, the number is much more variable than that. The snow we got here last night was probably 5:1 or lower, and we’ve gotten wetter stuff than that. The light, fluffy, dry stuff we get when it’s 30 below zero can be as high as 15:1. Yep. We got almost 4" of snow that melted down to 1/4" of water in the rain gauge.