Frigid temperatures in the city have prompted Toronto’s medical officer of health to issue an extreme cold weather alert.

The advisory was issued at around 7:30 a.m. on Thursday.

Environment Canada says Toronto will see a high of -6 C on Thursday but the temperature will feel closer to -18 with the wind chill. Overnight, the national weather agency says it will feel like -24.

In a news release issued Thursday, the city says the alert is in effect until further notice.

Toronto Public Health advises people to check on vulnerable family members, friends, and neighbours during the cold snap.

Those most susceptible to cold-related illnesses include people experiencing homelessness, outdoor workers, those with pre-existing heart conditions, elderly people, and young children.

The alert triggers a number of additional cold-weather services, including the opening of a warming centre at Metro Hall.

“Other services include notification to community agencies to relax any service restrictions, availability of transit tokens in some drop-ins, and additional overnight street outreach,” the city’s news release read.

There are also multiple 24-hour respites sites open throughout the year where people can sleep, get meals, and receive referrals to other services offered in Toronto.

“When the temperatures are this cold, even as low as -20 with the wind chill, that’s when we are concerned about things like hypothermia,” Dr. Christine Navarro, the associate medical officer of health for Toronto Public Health, told CP24 on Thursday afternoon.

“With prolonged exposure that can even result in death so that is really important to seek shelter, to stay warm, drink hot liquids, and dress in layers.”

At this time last year, the city had already issued 19 cold weather alerts over the winter season. So far this year, there have only been two.