Snow water converter
Convert snow depth into the water it holds. Pick the snow type first: a meter of powder is nothing like a meter of spring slush.
That's 1.5× as deep as a good covering, while a good ski base is 6.7× deeper. On a 10 m by 10 m roof that is about 1,500 liters of water.
What it means
How much water is that?
Snow density changes as a pack settles, so a measured depth converts differently on the day it falls and a week later.
Every unit
Your snow in every unit
Learn
Three things worth knowing
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Fresh snow is about a tenth water
The old "ten to one" rule. Cold dry powder can be twenty or thirty to one; wet spring snow is nearer two to one.
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Water equivalent is the roof load
A millimeter of water equivalent is one kilogram on every square meter. Roofs collapse under wet snow, not deep snow.
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Depth is not water
Quoting snowfall in centimeters without the type tells you nothing about the water, which is why hydrologists weigh cores rather than measure depth.
Shortcuts
Popular snow conversions
Background
About snow water equivalent
Snow depth says very little on its own. Water equivalent is what matters for floods, for avalanche work and for roof loads: how much water would be left if it all melted.
Fresh powder is about a twentieth water; settled snow a fifth; old spring snow half. So 50 cm of powder and 10 cm of spring snow hold the same water.