Winter Weather
Snow-to-Liquid Ratio Explained: Why One Inch of Water Can Make Different Snow Totals
Why snow ratios vary, what 10-to-1 means, and how temperature, wind, and snow crystal type change snowfall totals.
Quick answer: Snow-to-liquid ratio compares snow depth to melted water. A 10-to-1 ratio means 10 inches of snow melts to about 1 inch of water.
The 10-to-1 shortcut
Many people hear 10-to-1 as a default ratio, but real storms can be lower or higher.
Wet heavy snow may have a lower ratio, while cold fluffy snow can have a higher ratio.
What changes ratio
Temperature through the cloud, dendritic growth zones, wind, compaction, sleet, and rain mixing all affect accumulation.
Strong wind can break flakes and reduce measured depth.
Forecast impact
A small ratio change can shift snow totals a lot when QPF is high.
This is one reason snowfall maps can change close to the event.