Most sequels disappoint. The further into the sequence we get, the worse they can be. Parts three or four of a film series (Godfathers, Star Warses), presidents’ second terms, mayors’ fourth terms: all strike us at best as slight letdowns, at worst as betrayals.

So the eleventh snowstorm we had this winter, the fourth this February, came to us with low expectations indeed. Its predecessors had already given rise to more than enough clichés about Christmas, fears about snow days (would school now stretch into July?), apparently futile hours of upper-body exercise (why shovel if the driveway would only fill up again?), repetitive expressions of glee in our children (snowballs!), and equally repetitive yet comical exclamations of childish discomfort (snow pants!). The last ten-odd storms had already left behind toothy mountain ranges carved by the sides of the plows, along with a block-long series of mounds in front yards, as if advertising (or mocking) the warm, slushy Sochi Olympics. After such snows, what forgiveness? And what else was left for this latest weather to do?

It turned out to be a lesson in variety, and in close attention to what lay under our boots. New snow in big, wet flakes, piled atop a thin and dirty crust, itself thinly brushed atop the floury stacks left from last week and the week before, interspersed with ice-core slabs packed down by passing cars: it took all of these snows, one after the other, to make us take a closer look at the snow in the first place, and to drive home how many kinds there were. “Snow is to water what poetry is to prose,” writes the historian Bernard Mergen in Snow in America: it is at once more rare, less useful, more elaborately organized, and harder to describe. Only via snow after snow after another snow, thick enough to blow over itself and shelter some residues from dirt and plows and traffic, could we even visualize an inventory as we dug beside fences and under back stairs.

Given a magnifying glass (or just afflicted with myopia), we could try to distinguish the official classes of snowflake, as Mergen sets them forth: “Plate, stellar, crystal, column, needle, spatial dendrite, capped column, irregular column, irregular crystal, graupel, ice pellet and hail.” Snow on the ground undergoes its own metamorphoses, depending on when and how it melts and refreezes. The National...