The two years with the deepest average snow in the US were the years when El Chicon and Pinatubo erupted. I remember seeing pictures of Los Alamos, NM in 1993 – with cars completely buried under the snow.
But look what happened after those eruptions. In both cases, average snow depth plummeted over the next decade.
Also note that larger extent tends to produce lower average depth, because Mississippi is not going to get a lot of snow when it does snow there, and because very cold air contains less moisture.
Los Alamos is over 7,000 feet and gets plenty snow from time to time… Snowed 3 feet in neighboring Taos, at similar altitude, one weekend in the early 80s when I was a kid. More than an anecdote will be required on this matter.
I grew up in Los Alamos, and use to skate on Ashley Pond
You are probably thinking of the first weekend in November, 1980. I was skiing at Taos and the snow was already five feet deep.
School children have more chance of seeing snow now than they did in 1920. Not exactly what Dr. Viner predicted.