ELMWOOD PARK, Ill. (CBS) — Much of the Chicago area was under the National Weather Service’s red flag warning Tuesday, meaning “critical fire conditions are occurring now or may occur soon.”

Within the CBS Chicago viewing area, the red flag warning was in effect for Cook, DuPage, Will, Kendall, Grundy, LaSalle and Kankakee counties in Illinois, and Lake, Porter, Newton and Jasper counties in Indiana. Much of the state of Illinois, through Macomb, Peoria, Bloomington, Champaign and Danville, was also affected, along with much of northern Indiana and eastern Iowa.

Parks with lots of leaves on the ground — of which there are many in the fall — are the areas that first responders and weather experts say could be a problem during red flag warnings. There is a significant risk that those leaves, or the dry brush or grass, will catch fire.

The Elmwood Park Fire Department in Chicago’s western suburbs is prepared.

“All of our equipment is ready for anything that can happen, regardless of the weather,” said Michael Terzo, Elmwood Park Fire Chief.

But Terzo also emphasized that people, regardless of their preparation, should refrain from doing things that could ultimately require his department’s intervention.

“I wouldn’t recommend starting a fire outside,” Terzo said.

Terzo said while it’s great to enjoy the unseasonably warm weather, it’s also important to enjoy it safely. That means more caution, especially around piles of leaves and dry grass.

Cars may not be parked on or near such vegetation.

“They are dry around the house,” Terzo said. “All you need is a cigarette butt or a match to throw into a pile of leaves near your house – and off you go to the races you’re going.”

These conditions came with Temperatures will reach the lower 80s in Chicago on Tuesday– and on track to break a heat record of more than two decades.

The warm conditions together with the low humidity, the south-southwesterly wind of 25 with gusts of up to 60 km/h and the fact that it has not rained recently, exacerbate the fire risk.

“If it had rained yesterday, no red flag warning,” said Illinois State Climatologist Trent Ford, “because everything is completely wet, it won’t ignite.”

Ford said the warming climate plays a role in the high fire risk.

“A red flag warning is very similar to other types of weather warnings that we do take seriously, such as tornado warnings, flash flood warnings, severe thunderstorm warnings and extreme heat warnings,” Ford said. “Climate change is impacting increased fire frequency, especially at this time of year.”

Climate Central has found that fire weather days like Tuesday have increased locally as the climate warms. There were on average three more hot, dry and windy days in 2023 than in 1973.

“Under certain weather conditions, a spark and a fire can spread very quickly,” Ford said.

The Elmwood Park Fire Department had not received any calls regarding the red flag warning as of Tuesday afternoon. But in Kankakee County, a small wildfire broke out in Pembroke Township, sending smoke billowing into the air.