Chicago braces for dangerous cold as health officials warn frostbite can strike in 30 minutes

CHICAGO - Chicagoans woke up to brutal cold Wednesday, with wind chills plunging to nearly 15 below. Health officials say the conditions are dangerous and can become life-threatening in a matter of minutes.

What we know:

If you stepped outside at all today, you already know how brutally cold it feels. And doctors warn this type of weather can quickly become life-threatening.

Wind chills dropped to nearly 15 degrees below zero, and medical staff say frostbite can set in within 30 minutes, especially on exposed skin.

Visitors felt it too; Even a Canadian couple touring Chicago admitted the cold caught them off guard.

"No, we’re actually freezing right now. We’ve been miserable," they said. "We thought it would feel warmer because we’re Canadian… but it’s so cold."

Health officials are urging everyone to bundle up, no matter how long they plan to be outside. Kelly Monestero, RN, MSN, CEN, Director of Operations for the Emergency Department at Northwestern Medicine McHenry & Woodstock Hospitals, says preparation is key.

"You may feel fine, but anything can happen. Slipping on ice, falling, or being outside longer than planned," Monestero said. "If your dog runs off, now you’re frantically searching in dangerous temperatures. Be prepared whether you’re out for a few minutes or much longer."

Doctors say to pay close attention to exposed areas like the ears, nose and face, and to check on elderly neighbors and pets who may be more vulnerable.

RELATED: Subzero wind chills grip Chicago as warming centers open

Some Chicagoans are adjusting their plans, like Ana Carvatta, who decided to get her dog’s walk done early.

"We’re getting our walk in now so we can cuddle up inside," she said.

With more snow in the forecast, doctors are also warning about "heart attack snow" — heavy, wet snow that can put dangerous stress on the heart when shoveling. Monestero says it’s a real risk.

"When the snow is super heavy, it puts stress on the heart. Breathing in cold air narrows blood vessels, which can limit blood flow. Know your limits when you’re shoveling," she said.

Other visitors say they’re adjusting their plans too.

"We’re just planning on going back to our Airbnb," the Canadian couple added. "We’re trying to get the sightseeing out of the way before it gets too cold."

Doctors say if you have to be outside, listen to your body. Numbness, tingling or pain are all signs it’s time to get indoors immediately.

A full list of warming centers is available here.

What's next:

Chicago will stay cold through the week, with another chance of snow by the weekend. Temperatures are expected to remain below normal, and health officials say the risk of frostbite and hypothermia will continue as long as wind chills stay in the single digits or below zero.