I secured all the weathering so far with a spray bomb of Rustoleum flat clear enamel (a bit of an experiment, to see if there is a less expensive alternative to Testor's Dullcote [now owned by Rustoleum]). Then I waited patiently for four whole days (

). I received two bottles of AK Snow Microballoons. I imagined a fresh, light snowfall, pure white in contrast to the dirty KV-1. I brushed on areas of thinned flat lacquer in an attempt to affix the the snow, attending to areas where I know snow will stick in a wind, creating the look I know all too well as a born-and-back-again Wisconsinite (USA).
Trying to get even more effect of wind on the snow, I blew on the snow patches from the front of the tank to the back. Unfortunately, I blew all the snow off the tank. Quick, where are my nearly 70 birthday candles! ("Gasbag" you say?)
So I gobbed on the thinned flat lacquer even more and reapplied the snow. This time, I let the "wind" (a.k.a. a strong, but indirect fan on low speed) do the job. Still some snow flew---on the sleeping Schnauzer who was under another modeling table a few feet behind the tank.
Now reasonably satisfied, I took one of my airbrushes, set the pressure to 15 lbs., backed the pressure down almost all the way with an adjustment at the brush, and cautiously created some more windblown snow effect. I got not so much fresh snow as the look of snow a few hours later, perhaps after another road march. This is not exactly the look I had in mind when I started "snowing" on the tank, but I will

about this look for a while because it does suit the grubbiness.
So to end it all, I affixed the snow with a rain of Rustoleum clear flat lacquer, spraying over top of the tank and letting the lacquer settle down without blowing off more snow.