Getting to the facts: outdoor burning in Missoula County

Many property owners in Missoula County participate in outdoor burning, whether it is to regenerate a hay field or burn vegetative debris. With those crazy summer windstorms, many people have more tree debris to burn than normal - but you may have to wait until spring to burn it. Fall outdoor burning has different rules than spring burning. This article explains the different burning seasons detailing what is allowed in the fall versus the spring, as well as highlights safe outdoor burning tips.

Outdoor burning is simply burning natural vegetative material produced on a property - burning of trash, man-made materials, treated wood, or trade waste is strictly prohibited. All these things produce dirty smoke that is very bad for human health. Escaped and illegal debris burning is the leading cause of human started wildfires in Missoula County, so it is extremely important that landowners understand the county's burn permit system, seasons and safety measures required for burning.

What are the different outdoor burning seasons in Missoula County?

The General Outdoor burning season is March 1 to Aug. 31, conditions dependent. General outdoor burning includes burning vegetative material from a property, often from a garden or fallen branches from trees in a yard. In the Air Stagnation Zone, described below, piles of grass or deciduous leaves may not be disposed of through outdoor burning.

The Essential Agriculture burning season is March 1 to Oct. 31, conditions dependent. Essential agriculture burning is conducted on a farm or ranch to eliminate excess vegetative matter from an irrigation ditch or cultivated fields, or to improve range conditions or wildlife habitat. Agricultural burning should only be conducted when no reasonable alternative methods of disposal are available.

The Prescribed Wildland burning season is March 1 to Nov. 30, conditions dependent. Prescribed wildland burning is planned and conducted on forested land or relatively undeveloped range land to improve wildlife habitat or range conditions, promote forest regeneration, reduce fire hazards resulting from forestry practices, control forests pests and diseases and/or promote any other accepted silvicultural practices. Prescribed wildland burning that extends from December to February is considered Essential Prescribed Wildland burning, which requires a permit obtained directly from Missoula Public Health. Strict criteria must be met for this permit.

For all burning types, burners need to purchase or renew your burn permit for $7 online at the County Burn Permit and Notification Service website (https://app.egovmt.com/burnpermit/), or at your local fire department or Department of Natural Resources and Conservation Unit office. Before lighting your fire, you must activate your permit either online at https://app.egovmt.com/burnpermit/ or by calling 1-888-583-6497 for each location and on each day, you intend to burn. If burn restrictions are in place, you will not be able to activate your permit. Fires should not be lit until 9 a.m. and should be completely out by 4 p.m. Also remember that burning within Missoula city limits is only allowed on properties more than an acre.

Missoula Public Health's Air Program defines the burning seasons, opens or closes burning throughout the year and administers burn permits. Burning can be restricted even when the outdoor burning season is open. Restrictions are based on air quality conditions, weather and wildfire danger in Missoula County. To protect public health and ensure good air quality, burn restrictions during the outdoor burning season may vary throughout the county. Restrictions can limit burning by elevation, location and start/end times based on smoke dispersion conditions. For example, the Potomac Valley experiences frequent stagnant air and poor dispersion conditions, increasing the likelihood of burn restrictions there. Despite being in the same airshed, the air moves very differently in the Huson versus the Potomac Valley, thus differing restrictions may apply to burners there. There are three airsheds in Missoula County (2, 3A and 3B). Check out https://gis.missoulacounty.us/MCCHD/AirQuality/ to see the boundaries of airsheds and Impact Zones in Missoula County. Your permit will state which airshed you are in. Burning may also be closed due to fire danger at any time.

Kerri Mueller, air quality specialist with Missoula County, explains why it's important to adhere to burn windows.

"Outdoor burning is only allowed between the hours of 9 a.m. and 4 p.m. because of how weather changes when the sun rises and sets. Ventilation rates, winds and temperatures often plummet after sunset resulting in poor smoke dispersal conditions. If a fire smolders and smokes after 4 p.m., that smoke is likely to get trapped in the ground level air we breathe, poorly impacting our air quality and health. Once the sun rises, the sun warms up surface level air causing dispersion conditions to improve, which allows smoke to mix with the atmosphere more freely. Best practices are to build piles that will burn completely within the 9 a.m. to 4 p.m. burn hours, which helps avoid smoke being produced overnight. Each day is new and has different weather conditions than the last and some days just aren't good days to burn because the smoke isn't going to go anywhere. This typically looks like low mixing heights, low transport winds and very little change in temperature throughout the day or a mixture of them all that contribute to poor smoke dispersal conditions. It's important to check the restrictions each morning when you go to activate your burn permit each day you plan to burn."

Safe Debris Burning Tips:

· Remember to never burn around overhanging vegetation and surrounding tall grasses/ vegetation.

· Overhead clearance for piles should be three times the height of the pile. Ground pile clearance should be 10 feet of no combustible materials in all directions.

· Keep piles small and easily manageable. Add materials gradually.

· Keep shovels, water, fire extinguisher and tools nearby and never leave your pile unattended. Drown, stir, drown, feel, until your fire is completely out.

· Once you have completed burning, monitor your fire for smoke and heat thoroughly the rest of the day and until it is completely out.

· Check fire danger levels and fire restrictions that might be in place at MTFireInfo.org.

Montana DNRC Fire Management Officer, Ashleigh Burwick, explains, "Every year, local fire departments and wildfire suppression agencies respond to reports of escaped debris burns that result in a wildfire. It is important to follow local burn permit regulations anytime that an individual is wanting to burn. Don't burn when (it's) windy, have access to water and hand tools and ensure that the burn area is completely extinguished before leaving the burn unattended. Every year, there are also wildfires that are a result of an individual thinking that their burn has been extinguished, only to have the burn area rekindle in the subsequent days due to either a warming and drying trend, or an increase in winds, and often both."

For larger scale prescribed burns on public lands, such as those conducted by the United States Forest Service, Bureau of Land Management, DNRC, or "major burners," agencies must receive approval from an Airshed Coordinator with the Montana Idaho Airshed Management Group and a Missoula Public Health Air Quality Specialist.

The details of burning in Missoula County can be confusing at times. To learn more about outdoor burning seasons and permits, reach out to your local fire department or Missoula Public Health at (406)258-4755. Visit the following websites for more information:

Missoula Public Health: missoulapublichealth.org/environment/air/outdoorburning/

Missoula County Fire Protection Association: mcfpa.org/outdoor-burning-permits