Smoke and Drought Shut Down Alligator Alley as Big Cypress Wildfire Burns 35,000 Acres

State troopers closed the gates across Interstate 75 just after midnight, as smoke thickened over the asphalt and headlights dissolved into a gray wall. On that late February night, the only high-speed highway between Naples and Fort Lauderdale — a stretch of road better known as Alligator Alley — was impassable, choked by smoke and fog from a wildfire burning in the swamp to the south.

A fast-moving fire in an unusually dry winter

The blaze, known as the National Fire, has scorched more than 35,000 acres inside Big Cypress National Preserve since it started Feb. 22. It is human-caused, according to federal summaries, though investigators have not publicly said how it began. Fanned by record winter drought and feeding on frost-killed vegetation, the fire has transformed a normally wet, fire-tolerant landscape into one of Florida’s largest and costliest wildfires in recent years, forcing highway closures and sending smoke across South Florida.

As of March 7, officials estimated the National Fire at 35,027 acres and 67% containment, with suppression costs exceeding $4.5 million. No deaths or major structural losses have been reported, but the event has underscored how drought and human activity are reshaping fire risk in parts of the country better known for hurricanes than megafires.

“Ongoing wildfire activity within Big Cypress National Preserve continues to expand due to persistent drought conditions and recent frost damage that has created an unusually heavy and highly receptive fuel bed,” the National Park Service said in a Feb. 24 update.

Why Big Cypress burns — and why this year is different

Big Cypress National Preserve spans about 729,000 acres of cypress domes, sawgrass prairies, pine flatwoods and hardwood hammocks north of Everglades National Park in Collier County. Congress created it in 1974 as the nation’s first national preserve, a designation that protects its water and wildlife while allowing activities such as hunting, off-road vehicle use and traditional tribal practices by the Miccosukee and Seminole.

Fire has long been a natural part of that ecosystem. Many of the preserve’s habitats evolved with frequent, low-intensity burns that keep prairies open, recycle nutrients and curb the buildup of dense undergrowth. The park runs one of the largest prescribed fire programs in the National Park System, typically burning more than 60,000 acres each year under carefully chosen conditions.

This winter has been different. Much of Florida entered 2026 in extreme drought. State drought indices reached levels associated with very high to extreme fire danger, and soil and vegetation across South Florida were unusually dry. On Feb. 9, the governor signed Executive Order 26-33, declaring a statewide state of emergency for drought and wildfire risk and authorizing additional firefighting resources.

In Big Cypress, park managers halted prescribed burns as conditions deteriorated. Then, on Feb. 22, a fire started anyway.

Fighting the fire — and the smoke

By Feb. 24, the National Park Service said the National Fire was about 15,000 acres and uncontained. The blaze was burning south of I-75 between State Road 29 and Turner River Road in sawgrass, cypress and other Everglades-type fuels. Fire crews worked to hold it within a perimeter bounded by I-75 to the north, SR 29 to the west and interior roads to the south and east, building fire lines and conducting defensive firing operations along roads to remove fuels ahead of the advancing flames.

“Dry vegetation combined with accumulated frost-killed fuels is contributing to active fire behavior across the preserve,” the park said.

By Feb. 25 and 26, smoke from the fire was affecting several major roads — not just I-75, but also U.S. 41, known as the Tamiami Trail, and State Road 29. The National Park Service urged motorists to exercise extreme caution, slow down and use headlights in smoky areas, warning that visibility could suddenly drop to near zero.

Late on Feb. 25 into the early hours of Feb. 26, smoke from the fire mixed with fog over Alligator Alley, creating conditions similar to “superfog,” a dense, ground-hugging haze that has contributed to deadly pileups in other states. The Florida Highway Patrol closed a 57- to 80-mile stretch of I-75 overnight before reopening it when visibility improved several hours later.

Off the highway, smoke plumes spread well beyond the preserve. Satellite imagery showed a steady trail of haze stretching across South Florida. Residents in rural communities near Big Cypress and in urban areas farther east reported smoky skies and the smell of burning vegetation.

“I wear a pacemaker, and I’m concerned about breathing issues and I’m constantly concerned about environmental issues as they come up,” one motorist told a Miami television station while traveling Alligator Alley during the smoky period.

Health officials urged people with heart or lung disease, older adults and children to limit outdoor activity on the smokiest days, particularly in parts of Collier, Miami-Dade and Broward counties.

Evacuations, infrastructure questions, and a broader trend

At least one small community, Jerome, west of SR 29, was placed under voluntary evacuation, according to incident summaries. Larger population centers such as Naples and the Fort Lauderdale area did not receive evacuation orders.

State emergency officials also fielded questions about a state-run immigration detention facility along Alligator Alley, sometimes called “Alligator Alcatraz.” Stephanie Hartman, a spokesperson for the state’s emergency management division, said the facility was not in immediate danger.

“The fire is situated 20 miles to the west of the facility and is burning in the opposite direction,” she said, adding that increased humidity later in the week was helping firefighters gain control.

The National Fire is one of more than 650 wildfires reported across Florida so far this year, according to the Florida Forest Service. Nationally, firefighting agencies say the United States has seen significantly more wildfires in the opening months of 2026 than during the same period last year, reflecting what fire managers describe as a lengthening and less predictable fire season.

Scientists caution against attributing any single fire solely to climate change. But they say a warming atmosphere tends to increase the odds of prolonged droughts and heat that can turn landscapes into tinder, even in regions that are typically wet. In South Florida, shifts in rainfall timing and intensity can leave wetlands drier for longer stretches, exposing peat and roots and making ecosystems more vulnerable to severe burns.

In Big Cypress, that means fires may behave differently than in the past. While many native plants, including sawgrass, are adapted to survive and resprout after fire, managers worry that repeated high-intensity burns during deep drought could damage soils, kill mature trees and alter habitat for species such as the Florida panther and wading birds.

Recovery — and what it means for Florida’s future fire risk

The National Fire has also highlighted the tension between keeping wildlands accessible and reducing human-caused ignitions in high-risk periods. The preserve’s enabling legislation directs the National Park Service to protect its natural, scenic, hydrologic, floral and faunal values while allowing hunting, off-road vehicle use and tribal activities. Investigators have not said whether this fire began with a campfire, vehicle, debris burning or some other source, but officials have repeatedly described it as human-caused.

As crews continue to strengthen containment lines and mop up hot spots, attention is turning to recovery and preparation for the next dry spell. Charred sawgrass will likely green up quickly once rains return, and some areas may benefit from reduced fuel loads. Other patches, especially where peat burned deeply or trees were killed, could take far longer to recover.

For drivers on Alligator Alley, the experience has already changed how they think about crossing the state. What was once a quick drive past cypress domes and alligator-lined canals has, at least for a few nights, been a reminder that in a drier Florida, even the swamps can burn — and the safest route from coast to coast can vanish into smoke.