Republic of Mathematics blog

5" of snow: is that a lot of snow?

Posted by: Gary Ernest Davis on: February 10, 2010

It’s snowing heavily here in Dartmouth, Massachusetts. Forecasts are anything from 5″ – 12″ of snow before it eases overnight.

Is 5″ of snow a lot of snow? Let me tell you, when I’m shovelling it, it seems like a lot! Could we compare 5″ of snow with something else – like water, for example.

My driveway is about 20′ by 40′ – 800 square feet, or  800\times 144= 115200 square inches.

So, a layer of 5″ of snow on my driveway is about  5\times 115200 =576,000 cubic inches.

That’s a lot of cubic inches.

How much water would that be? Typically, fresh snow is about 10% the density of water.

So 5″ of fresh snow on my driveway is equivalent to about  57,600 cubic inches of water.

There are 231 cubic inches in a US gallon, so there would be the fresh snow equivalent of \frac{57600}{231}\approx 249 gallons of water sitting on my driveway – say 250 gallons between friends.

That’s about 4\frac{1}{2} 55-gallon drums of water.

Seems like quite a lot of water.

Certainly feels like it when I’m shovelling!

This blog post was prompted by the conjunction of two events, one predicted, the other entirely unexpected.

The first event was the snow, which was accurately forecast.

The second event was John Allen Paulos retweeting me on Twiitter.

John Allen Paulos

That was pretty cool, and I was thinking about his books as I shovelled snow and – boing! – I wondered how someone who had never see snow could relate to 5″ of the white stuff on my driveway.

2 Responses to "5" of snow: is that a lot of snow?"

Call it 250 gallons of water.

A gallon is eight pints, and the density of water is one pound per pint (or a convenient 16 oz. per 16 fl. oz.).

(250 gal.) x (8 lb./gal) = 2000 lb. = 1 ton of snow.

That’s roughly correct, and helpful if a person can relate to a short ton.

A US gallon of water is more like 8.35 pounds, and so 250 gallons is about 2087 pounds which is a bit less than midway between a short ton – 2000 pounds – and a long ton – 2240 pounds.

Of course a uniform 5″ of snow was also only a rough estimate.

Whatever helps people relate 5″ of snow on a driveway to something else they can understand! If they know about tonnage then that image should be helpful.

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