The bitterly cold temperatures are posing a special risk to people living on the streets. NY1's Vivian Lee tells us about what's being done to prevent people from freezing to death.

With the wind chill Friday morning, Union Square felt about 10 degrees.

And with the city issuing a code blue alert, outreach workers are checking in on the homeless more frequently now and through the weekend, when it is supposed to turn even colder.

The workers are ready to call 911 and force someone inside with the help of EMTs and police if that person does not satisfy a safety checklist.

"Whether they're shivering or shaking, an individual indicating they're cold. Are their clothes wet, which would get them colder faster?" said Cesar Vanegas, the director of Manhattan Outreach Consortium, listing off some of the signs they look out for.

"Do they know where they are? Do they know how cold it is?" he continued. "Can they say they're taking measures to keep themselves warm, and what the plan is for the next day?"

Code Blues are declared when the temperature falls below freezing. The designation relaxes intake rules at city shelters.

Dozens of outreach workers with a consortium of community groups under a city contract fanned out overnight across Manhattan, a magnet for people living on the streets.

"There's more populated areas — busier, metropolitan areas of the city — as opposed to the other areas," said Lauren Taylor of Manhattan Outreach Consortium.

Often, folks who notice a homeless person in trouble will flag the workers down.

Thursday night, 30 people were approached, and eight were taken to shelters.

The work is done in eight-hour shifts, 24/7, and is not for the faint of heart, because of the bitter cold the outreach workers themselves face.

But they said the Code Blue only intensifies the work they do every day, with or without the advisory, checking in on as many homeless people as possible and ensuring no one is in danger of succumbing to the punishing temperatures.