There have been four outdoor deaths since sub-zero degree weather hit the city on Friday, according to the Department of Public Health & Environment.

It is too early to tell whether the deaths are cold weather-related, a public health department spokesperson said.

“Not all of these cases are suspected to be people experiencing homelessness,” the spokesperson added.

The deaths await toxicology and coroner reports.

Temperatures plummeted to below zero degrees Friday night and into the weekend.

A north wind with a windspeed of around 6 mph will bring wind chill values as low as -24 degrees.

Avoid outside activities, if possible. When outside, make sure you wear appropriate clothing, a hat and gloves.

Additional mountain snow will continue through Sunday night. Westerly winds will likely produce wind gusts up to 45-55 mph for areas above 10,000 feet. These conditions may lead to areas of blowing snow along mountain passes. Be prepared for winter driving conditions; postpone or delay travel if possible.

Another round of light snow will begin Sunday night, spreading across the entire plains. Snow accumulation through tonight will be up to 1 inch mainly for areas above I-76. Dangerous wind chills are possible overnight between -20 to -30.

Periods of moderate to heavy snowfall will continue in the mountains on Monday but should begin to decrease in the afternoon. Meanwhile, light snow will spread across the plains on Monday behind another surge of arctic air.

Frigid conditions will continue through Tuesday morning, as low temperatures drop well below zero. Wind chill readings during this period will be dangerously cold, with frostbite potential on exposed skin in as little as 10 minutes. Temperatures will begin to moderate across the plains by Tuesday afternoon into Wednesday.

Another round of snow will occur in the mountains later Wednesday into Thursday.

Denver International Airport reported 257 flights were canceled as of 4:37 p.m. Sunday while 538 other flights were delayed, according to flight tracking site flight aware.

There have been 609 flight cancellations, and counting, out of Denver International Airport between Friday and Sunday.

On Friday, there were 191 canceled flights and 720 delayed flights at DIA. On Saturday, there were 161 flights canceled and 756 flights delayed, according to the flight tracking site.

DIA had the most amount of cancellations and delays, both for outbound and inbound flights, of any U.S. airport on Sunday, according to flight aware.