Literally almost everywhere above 5,000ft gets snow in winter, even in the high deserts occasionally (eg. Monument Valley, Painted Desert etc). So in a conservative guesstimate (knowing over 1/3rd of AZ is above 5k ft), 20,000-38,000 sq miles of land in AZ gets yearly snow with extreme events covering over half the state every few years (El Nino years). The heaviest snowfall usually occurs between 7,000ft-11,000ft, and going by land area alone the majority of snow actually falls on high plateaus whilst highest totals occur on mountains.
AZ peak statshttps://listsofjohn.com/PeakStats/countystats.php?sort=n&State=AZ