Thread on snow ratios. The snow ratio, or snow-to-liquid ratio states how many inches of snow, when melted, yields one inch of liquid water. Ratios are usually around 10:1 or 12:1, but can vary from as little as 6:1 or as high as 30:1, or sometimes more. 1/

There's a common misunderstanding that the colder the surface temp is, the higher the snow ratio will be (fluffier snow). This is incorrect. As long is the surface temp is not close to freezing, it really doesn't matter all that much. 2/

As the surface temp gets close to or exceeds freezing, more snow is lost to melting, yielding lower ratios and heavy, wet snow. The same reasoning also applies to temps above the ground; if they exceed freezing, sleet or rain can mix with the snow, dramatically lowering ratios 3/

Much more important is the dendritic growth zone (DGZ), the layer of the atmosphere with temperatures between -12 and -18C. In this layer, snowflakes grow as dendrites, which can easily clump together into aggregates, which contain a lot of air, increasing the ratio 4/

At warmer or colder temps, the flakes grow as plates, columns, or needles, which don't clump together as well and contain less air, lowering the ratio. To make this even more complicated, there's also a dependence on atmospheric humidity. 5/