When it snow 10 inches does that actually equal one inch of rain?

I’m sure you’ve heard that claim. It is a commonly shared belief that seems to get regurgitated every time it pours cats and dogs or snows feet.

But, is the legend true?

The quick answer: sometimes.

When the temperature is around 30 degrees, one inch of liquid precipitation would fall as 10 inches of snow -- assuming the storm is all snow.

But, the amount of moisture in each snowflake differs depending on the temperature changing the snow to rain ratio.

For example, our big December snowstorm occurred with temperatures closer to 25 degrees. During that storm the snow ratio was closer to 15 inches of snow to one inch of rain. We had 1.75 inches of "liquid equivalent," yet ended up with 23.2 inches of snow, not 17.5 inches of accumulation.

In fact, I took this into account when forecasting 15 to 25 inches from the Philadelphia area southward for the storm. We even showed a graphic on-air explaining those estimates.

We've had storms with snow closer to 20 degrees -- moving the snow ratio closer to 20 to one. And, when it's warmer (35 to 40 degrees), the ratio moves to 5:1.

Using a rule of thumb that each 10 inches of snow, if melted, would produce one inch of water

4" = 1" - Calculted snow to water volume in inches in a 32 degree enviornment

10" = 1" - Recognized as the average estimation of snow to water volume in inches

20" = 1" - Calculted snow to water volume in inches in a 10 degree enviornment

Each inch of snow produces about 2,715 gallons of water per acre

Chicago 1"= 3.69 billion gallons

The American football field, including end zones, is 360 feet long by 160 feet wide, so the area is 57,600 square feet. This is 57,600 cubic feet of water or 430,877 US gallons, about one and a third acre feet

How much water would it take to fill Dallas Cowboys Stadium ?

The Cowboys Stadium site covers 73 total acres; the overall site encompasses 140 total

acres.

The stadium is 3 million square feet containing 104 million cubic feet of volume.

Stadium length – 900 feet from one end zone retractable wall to the opposite end zone retractable wall.

The Math

1 Cubic Foot= 7.5 gallons of liquid. There is a 104 million cubic feet in the Stadium so times 7.5 gallons by 104 million cubic feet and you would get 1,050,000,000 gallons of liquid to fill the Dallas Cowboys stadium.

Sidetrack - Visualizing Million Drops of Water

10 drops of water +/- = 1 milliliter

10,000 drops = 1 Liter

1,000,000 drops = 100 Liters

and 1 Gallon = 3.5 Liters,

so 1,000,000 drops of water = 28.5714 gallons