Wednesday is another First Alert Weather Day in New York City due to dangerously cold temperatures. Wind chills can drive temperatures to near zero. 

The cold brings risk of hypothermia, frostbite and even a heart attack. 

Warning signs to watch out for 

You're certain to feel the brutal cold when you step outside. Love it or hate it, the deep freeze can be unsafe and, in some cases, deadly. Medical experts say children and older adults are especially vulnerable. 

"Signs of frostbite are a pale, cool extremity, like your finger, your toe. And it can actually lead to permanent damage, or losing a limb even," said Dr. Alina Metina, an emergency room physician at Hackensack University Medical Center. "If you start shivering, if you get confused, if you have a walk that seems unsteady, definitely go to the emergency department." 

Wearing layers of clothing is key to combating the cold, especially for those who have to be outside for long periods of time. 

Doctors say alcohol doesn't help. In fact, it gives your body a false sense of warmth. 

"If you are having a low body temperature and you are intoxicated or mentally impaired, you might not realize the stress your body is going through. And that could lead to a very, very dangerous outcome," Metina said. 

NYC activates "Code Blue"

This kind of cold has prompted a "Code Blue" across the five boroughs. That's when New York City Emergency Management activates extra protections for people most at risk, especially anyone without heat or shelter. Outreach teams are dispatched overnight and during the day, trying to get people indoors and into warming centers before the cold takes a toll. 

"In the case of cold weather, one of the big concerns is always homeless New Yorks," outgoing Emergency Management Commissioner Zach Iscol said. "Shelters become open to all homeless New Yorkers. We have some additional outreach teams that go out around the city looking for homeless New Yorkers." 

About 70 Code Blues get issued each season, officials say. 

If you or someone you know needs a warm place to go, you can call 311 to find the nearest warming center. 

Cold will linger 

One of the bigger concerns related to this cold snap is that it seems to be part of a pattern. There's no immediate relief in sight, with the cold air locked in through the weekend. That means more cold days, more strain on heating systems, and more risks if you're outside too long. 

More things to be mindful about: A cold snap can also lead to burst pipes, so make sure your home heating system is functioning properly. If the heat goes out, call a plumber, but leave the faucet on a slow drip, which will help keep the pipe from freezing. 

Portable heaters can also be of help, but don't leave them on while you're sleeping, and make sure they're plugged in directly to an outlet, not an extension cord, and are three feet away from curtains or beds. And, of course, don't use your oven to heat your apartment - any malfunction can lead to either a fire or carbon monoxide poisoning. 

And if you're hitting the road, it makes sense to make sure your car has some tools to help combat the cold, including a blanket, extra clothes, antifreeze, a shovel, scraper, and kitty litter, which is an inexpensive way to get traction on snow and ice.