Health officials warned Long Islanders to be especially careful as temperatures are expected to plunge into the single digits in the coming days.
"It's all common sense but you just want to remind people: not to excess," said Dr. Lawrence Eisenstein, Nassau health commissioner.
If you must go outside as temperatures drop, dress in layers, don't stay out too long and watch for signs of hypothermia and frostbite, he advised.
The elderly, the very young and people with chronic conditions, including heart disease, heart failure and diabetes, are especially vulnerable to extreme cold, said Dr. Steven Walerstein, chief medical officer at Nassau University Medical Center in East Meadow.
"Their risk is magnified and they should speak with their physician as to how far they need to be cold avoidant," he said.
Officials reported that few people came to warming centers after the storm. Hempstead's 13 warming centers drew eight people as of 2 p.m. Friday, town officials said.
But Eisenstein said people should check on their neighbors -- especially the elderly ones -- to make sure they have enough heat and food.
Grace Kelly-McGovern, a spokeswoman for the Suffolk County Department of Health Services, also warned people using space heaters or their fireplaces to keep children away and make sure chimneys are venting properly to avoid carbon monoxide poisoning.
Dr. Nirav Shah, the state health commissioner, urged New Yorkers to be extra careful with snow removal because frostbite and hypothermia can set in faster in colder weather.
Signs of hypothermia in adults may include shivering, exhaustion, confusion, fumbling hands, memory loss and slurred speech. In infants, it can include bright red, cold skin and very low energy.
To prevent frostbite, get out of the cold at the first sign of redness or pain, experts said. Signs of frostbite can include white or grayish skin, skin that feels unusually firm or waxy, and numbness.
Dr. Alan Kaplan, director of emergency services at Plainview Hospital, said people who are usually sedentary should be careful not to overexert themselves. And with expected higher temperatures Sunday followed by lower temperatures Monday, there is the risk of ice, he said.
"As people go outside and shovel to clear out their walks, you see a lot of falls," he said. "It's all simple stuff but you need to wear appropriate shoes and walk gingerly."
Dr. Brian Pinsky, a hand surgeon at Long Island Plastic Surgical Group in Garden City, warned people not to clean clogged snowblowers with their hands, even if they are turned off. He said he had treated three patients Friday at Winthrop-University Hospital in Mineola with deep cuts to their fingers. He said even turned-off blowers can have residual torque that can cause the mechanism to spin once it's no longer clogged.