Some Russians here have found it difficult to believe that enough snow has fallen in America to bring New York, Boston, Washington and other major cities to a halt. There is a widely shared local view that nowhere does it snow more than in Russia, where cities are never paralyzed. Besides, those things just don't happen in America, regardless of what the television says.

In truth, and it is painful to say, we who came expecting legandary snow and cold have found that that was happening at home So far 1977-78 has been a mild winter in Moscow. Scudding clouds poured rain in November, then in snowed heavily early n December, seeming to presage the kind of weather for which our imaginations had ampty prepared us. Around Christmas, the skies brightened and it go much colder.

In January the temperature was consistently below freezing, and the Moscovities announced with pride and relief that "hard frost" had at last arrived. Those were the days hailed as having "10 degrees of frost," when people stamped in happily shaking the snow from their overcoats, declaring with satisfaction, "This is genuine winter weather!"

Such weather usually brings to an end the flu and intestinal bugs that ride the wind; people are happier because they are more sure of their health.

One could safely store food on the balcony in string bags, thus expanding the larder. But their pride was misplaced when an unexpected thaw in mid-january melted the ice cream n the balcony refrigerators and set people to fretting again about their health. The unsettled pattern has continued this month, with very little snow, some rain and a number of days that could be considered balmy by any Northeasterner's standards for a February.

TASS, THE OFFICIAL government press agency, made the straight-faced pronouncement the other day that because of its superior environmental controls, Moscow dumps few [TEXT OMITTED FROM SOURCE] impurities on itself than do other major industrial cities of the world, thus explaining why the snow in the city lay so white for so long. This statement appeared on a day when the snow had seldom looked dirtier or more crestfallen, and the air was misty with assorted stack gases and effluvia. Even the city's most revered park, the Lenin Hills south of the Kremlin, looked covered in fly ash.

But never mind. Any snow brings out horders of skiers and sledders, as well as the ever-present strollers and joggers. Daring young men try to emulate Swedish slalom skier Ingemar Stenmark, rocketing down the city's few sloped down the cross-country skis, most incapable of making a turn if their life depended on it.

Shooting across their path are well-bundled children perched atop the small unsteerable sleds the Russians use. With shapkas , or fur hats, pulled down over their heads, coats buttoned to the throat, and thick scarves wound around their necks and tied behind, the sledders seem virtually indestructible. The sleds collide with bushes, trees, skiers, strollers, other sleds. The children fly off in all directions like human jelly beans, pitch into the landscape and then trudge uphill for another fling. It is harrowing to watch.

A WONDERFUL ASSORTMENT of anthropomorphic machines are used here to clear snow from the city's streets. There are truck-mounted machines that snuffle snow in their mouths, then blow it out sideways, or straight forward, or casually over the shoulder. There are gobblers that feed snow onto a conveyor belt with small metal arms, and there are V-formation flocks of plows that sweep invincibly down the widest streets, pushing everything out of the way, including on rare occasions, cars and their occupants.

Despite these technical marvels, Muskovites have been complaining that the snow this winter just isn't being picked up the way it used to. But then, they reluctantly admit with a sly smile, it hasn't been snowing like it used to, either.