The snow is melting. Spring has almost sprung! The mercury pokes upward, and New Yorkers’ spirits rise apace. It would be understandable, after this winter that seemed delivered from deepest Siberia, if all city dwellers walked around with upturned faces, basking in the sun’s rays. But the last throes of winter require having a care for what lies underfoot.

“If you don’t look down,” advised Valerie Bryant, 64, a home health aide from Cypress Hills, Brooklyn, “you don’t know what you’re stepping on.”

Before showers — certainly before flowers — there comes that ill-defined time that the fashion houses have seen fit to call “pre-spring,” but that New Yorkers know as the week or two when black snow wanes into black puddles, and the sins buried beneath February’s snowstorms reveal themselves in March’s squalid muck.