As fires burn across the state, what is mop-up?

As more than 100 wildfires are burning across the state, the phrase “mop-up” gets tossed around a lot as firefighting crews gain ground on containing a fire.

But what does it really mean?

No, firefighters and Florida Forest Service crews aren’t standing outside with mops and buckets cleaning up the remnants of the fire. It’s much more tactical than that.

In the most basic terms, mop-up is described as the extinguishing or removing of burning material, standing dead trees and hot spots near the controlled containment lines. It helps ensure anything that might still be burning underground doesn’t spread and contains the smoke and fire’s edge.

In practice, it’s using a lot of water and foam to suppress and suffocate anything that might still be burning, but can’t always be seen to the naked eye.

“Basically mop-up is consisting of making sure that everything smoldering is cold out, so it can’t reignite any of the fuels that are unburned interior later on when we’re not here,” said Chris Taylor, a senior forest ranger for the Myakka River District of the Florida Forest Service.

Taylor spent Wednesday morning doing mop-up at the Linger Lodge fire.

The fire sparked last week and has been mostly contained, but what’s been giving rangers like Taylor fits has been the hot spots that keep popping up.

Deciding where to start with mop-up includes a look at the scene. If there are any open flames when they arrive, crews will put those out immediately. Then they evaluate activity on the containment line, wind direction and any values that may be at risk downwind.

“It’s probably not the most glamorous part of fighting wildfires, but it’s the most important,” said Patrick Mahoney, public information officer for the Myakka River District of the Florida Forest Service.

Equipment wise, Taylor said they’ll use hand tools if they have to, to keep from putting their hands into the duff to move vegetation around and trucks equipped with foam and water. East Manatee Fire District has been helping out a lot with the Linger Lodge fire, Taylor said.

He explained that crews have been using a lot of foam.

Part of that problem has been the duff layer or vegetation that has fallen to the ground that can easily burn. They’ve been using more foam to suffocate the fire because of the deep duff layers, Taylor said.

“On a couple of these fires we’ve been seeing lately, the duff layer is burning, it’s not even giving off any smoke. So it’s really tricky, really sneaky,” Taylor said. “You think you’ve put it out and you come back and it’s smoldering again.”

Taylor pointed to one hot spot that he said he put out two days prior, but Wednesday, it was showing smoke again.

On a mostly blackened ground, browned pine needles that have dropped from trees in the area also cause issues when they fall. They can cause a fire to rekindle and restart.

Crews check the duff by cold trailing — using their hand to feel for heat near the ground for hot spots. Typically, Taylor uses an infrared thermometer to test the ground’s temperature, rather than his hand.

Burning duff will allow the fire to spread, burning out the bottoms of trees, causing them to fall over. Getting down to the sand and soil is the goal; there, nothing burns.

The tactics can change quickly during mop-up, depending on what and where things may be burning.

“The last few days of working on the mop-up of this fire has been exactly that,” Taylor said.

As of Friday, Florida Forest Service statistics showed more than 100 active wildfires in the state. From Jan. 1 to May 14, there have been more than 2,000 wildfires.

Manatee County is currently under a burn ban.

This story was originally published May 21, 2017 at 5:14 PM with the headline "As fires burn across the state, what is mop-up?."