Three Chicagoans died from cold-related causes during this week’s brutal polar vortex, bringing Cook County’s cold death tally to at least 23 people since the start of the season.

The most recent cold-related fatality happened early Friday in the Edison Park neighborhood on the Northwest Side.

Linda Czech, 62, was pronounced dead at 1:10 a.m. in the 7200 block of West Greenleaf, according to the Cook County medical examiner’s office. Czech, who lived in the same block, died from coronary disease, with lung disease and cold exposure serving as contributing factors, according to an autopsy conducted Friday. Her death was ruled an accident.

On Thursday afternoon, the frigid conditions caused the death of a 73-year-old woman in the Portage Park neighborhood on the Northwest Side.

Joanne O’Donnell was pronounced dead at 4:12 p.m. in the 3900 block of North Meade, where she lived, according to the Cook County medical examiner’s office. An autopsy conducted Friday found O’Donnell died from cold exposure and her death was found to be accidental.

About 6 hours earlier, cold exposure contributed to the death of a 92-year-old man in the South Side Brainerd neighborhood.

Jimmie Flewellen was pronounced dead at 10:02 a.m. in the 9400 block of South Parnell, the medical examiner’s office. Flewellen, who lived in the block, died from cardiovascular disease, with cold exposure-related hypothermia contributing to his death, according to autopsy results released Friday. His death was also ruled an accident.

Between Tuesday morning and Thursday morning, Illinois hospitals treated 144 patients for cold-related symptoms like hypothermia and frostbite, according to Illinois Department of Public Health spokeswoman Melaney Arnold. One person outside of Chicago was presumed to have died.

Last fall and winter, 47 deaths were found to be at least partially cold-related between Oct. 1, 2017, and April 1, 2018, according to the medical examiner’s office. More than 250 people have died of cold-related causes in Cook County since 2006.