You ARE cherry picking. Why the hell are you choosing 1956? And when you add twenty years to that, 1976, 1996, 2016... the numbers go up only because of COINCIDENCE.
The 1950s were MUCH snowier than you think they were, too! Here are the ten-year averages, also graphed below:
1891-1900: 27.1" 1901-1910: 23.1" 1911-1920: 23.0" 1921-1930: 20.0" 1931-1940: 21.0" 1941-1950: 18.5" 1951-1960: 18.5" 1961-1970: 26.5" 1971-1980: 14.5" 1981-1990: 15.4" 1991-2000: 16.3" 2001-2010: 18.0" 2011-2020: 14.9" 2021-2025: 6.8"
The UHI effect isn't negligible, but it should NOT cause this steep of a decrease in snowfall!