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Anatomy of a Prescribed Burn

Beginning a burn on one of two hundred piles.

Garden Mountain near Crouch, Idaho ~ November 2, 2017 – Bureau of Land Management sent out notices of prescribed burns that could happen from mid-October to mid-January on Garden Mountain after recent commercial logging. These burn practices are vital to reduce the fuel on the ground.  Burning of slash piles will help keep nearby homes safer in the event of lightning or human caused wildfires.

Many small slash piles line the road on Garden Mountain BLM land.

A prescribed burn follows a prescriptive set of carefully calculated objectives and timing that are decided by a whole host of safe burning criteria.  Timing of weather events is an important factor which can make or break a prescribed burn. Rain is considered a good thing in the eyes of BLM fire crews.

A slash pile ready for ignition.

Recently, BLM invited me on a tour of a planned prescribe burn on Garden Mountain just northwest of Crouch, Idaho. Wet weather in the forecast made the project a go and gave me the opportunity to physically see what a prescribed burn entails. Pages of documentation are followed to a “T” as the fire boss instructs the rest of the crew what needed to be done and where.

It started out as a chilly morning with a light drizzle. I was required to dress in fire protectant issued clothing and “good hiking boots”.  I joined up with other BLM crew members and Michael Williamson of BLM Public Affairs to go on the drive up Garden Mountain in a quad ATV. Roads were getting wet and nasty. No windshield in the ATV added to the cold along with mud spatters flying around. Everyone laughingly agreed this was “more fun than sitting behind a desk.”

We arrived at the designated BLM land that was logged commercially last year. The logging company uses a GPS to identify each slash pile placement, creating a map for BLM to use. Close to 200 slash piles were placed mostly along the six miles stretch of dirt road. Some piles were larger in more open spaces.  The crews plan to light at least 90% of these piles.

For a time the clouds lifted a bit and there was a slight view of Garden Valley. Most of the day was spent in the clouds at over 5,000 ft.

Drip Torch used for lighting slash piles.

Cheryl Bright, Fire Fuel Technician, aka Burn Boss to the rest of the crew, explains, “The dry weather recently makes it important to see how that has affected the fuels. We know we have rain coming in that can help keep smoke in check and dampen things down.  A test fire is a required part of the burn. It is written in the burn plan along with a required checklist of what the weather is like, the temperature, the humidity. We always do this before we ever start lighting a bunch of stuff on fire.  I like to burn ahead or during a storm because the atmosphere is more active, and the smoke will tend to go up.”

All prescribed burning for an individual day gets put into a computer system that is monitored by Idaho and Montana groups that include meteorologists.  They look at the weather and decide what the smoke dispersion will be. Condition approval must be met before the burn is ignited.  Once the crews are on site, they watch what the atmosphere is doing with the smoke from the piles. Bright goes through every element of the burn plan including safety, smoke management and duration.  A chart to will help rate low, moderate or high.  A complexity analysis of the objectives is decided before getting started.

Michael Williamson, BLM Public Affairs Specialist (left) speaking with Cheryl Bright, Fire Fuel Specialist discuss the project before moving on.

Crews light a couple of smaller slash piles with a drip torch and lighter as a “test” to see how the fire responds. The biggest thing they look at is to make sure there is no “creeping” of the fire beyond a certain distance of each pile. They also watch how the fire consumes the pile.

The first test pile was not responding in the way they liked and waited for a bit to try again. As the drizzle kept falling, the second pile was responding better.  The rest of the 200 piles were lit and closely patrolled all day. Most piles burned clean, hot and fast. At the end of the day, the first burn piles were almost gone, which is exactly what BLM crews want to see.

Six miles of piles along the road.

Each prescribed burn is carefully thought out, including wanting little disruption to the public. Neighboring subdivisions adjacent to the BLM land were notified of the upcoming burn. Signs were posted at the roads leading up to the area. Before leaving the site, crews made sure things were safe and eventually we all called it a day around 5:00 in the evening.

The slash pile has been burning up with little “creeping” distance from the pile.

In a nutshell, the goal for commercial logging is to get rid of dead or unhealthy trees and thin out the forest, thereby creating a healthier forest and one that has less wildfire potential and easier to fight any fires that may happen. The prescribed burns help to get rid of unnecessary fuels that could spread fires quickly if left on the forest floor. It is all about maintaining a healthy forest adjacent to rural suburban living.

Written by Janet Juroch 

Yep, that’s me “watching” fires.