A warning for the 60,000 runners and walkers expected to participate in Georgia’s biggest July 4th tradition: The 43rd Peachtree Road Race is under a heat alert.

A system of colored flags dotting the Atlanta race route will alert runners if the weather becomes too hot to safely complete the competition.

Green, yellow, red and black colored flags will indicate race conditions—from good to extremely dangerous. Race director Tracy Russell says flags will mark every water station:

“We’re going to be starting in yellow color which translates to moderate level, less than ideal conditions and we encourage participants to pay attention in case we have to increase level to red.”

A 7:30 AM start time maximizes activity during cooler, morning hours. The local high is expected to reach 93 degrees Wednesday.

Lee Alford from Peachtree City is running the Peachtree for the 18th time. He says he should be done before the real heat sets in:

“I train at different times of day, so I think I’m ready for it. I’m in the H wave, so I’ll be starting at 8 and should be done by 9, so hopefully I’ll beat the heat.”

According to race officials, 92% of the Peachtree Road Race’s runners are from Georgia.

Tags: Peachtree Road Race, parker wallace, heat alert