Howard Smith dug his shovel upright into the snow and stared admiringly at the strip of sidewalk before him. The path in front of his Upper East Side building was fully cleared and wide enough for a double stroller.

“Now that’s a beautiful sidewalk,” he said.

Mr. Smith is 91 years old, and still handles snow-clearing duties himself. After decades of digging, he has developed a few cardinal rules.

“What you want to do is mark your line from the top and then scoop it from below,” he explained, tossing a clump of ice to the side. “And salt is absolutely crucial.”

A few passers-by offered to lend Mr. Smith a hand, but he politely demurred.

“The key for me is to use a small shovel,” he said. “I want a safe sidewalk, not a heart attack.”

91-year-old Howard Smith shoveling his sidewalk after the storm pic.twitter.com/UtgX1pcWLN

— Noah Remnick (@NoahRemnick) January 24, 2016