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About Applegater. (Jacksonville, OR) 2008-current | View Entire Issue (May 1, 2012)
20 Spring 2012 Applegater Burning answers BY roB BuDGE Have you seen the Gater’s online calendar? www.applegater.org This time of year, I get lots of questions about prescribed burning from members of the public. Three of the most frequent are: “Why is the weather forecast that the Forest Service (FS)/Bureau of Land Management (BLM) use sometimes different from the one posted on the National Weather Service’s website?”; “How does the FS/BLM get clearance to burn?”; and “How come the FS/BLM are allowed to burn when there is an air stagnation advisory?” Hopefully, the following explanations of the smoke management process will help answer these questions. Weather forecast When the FS/BLM wants to conduct a prescribed burn (whether it be the burning of slash piles or a low underburn on the forest floor), the first thing we do is consult the weather forecast that is produced by the National Weather Service (NWS). The state of Oregon is divided into 32 distinct fire weather forecast zones. Every morning at about 6 am a weather forecast is issued for each zone for that day and several days into the future. After consulting the forecast, the Burn Boss (the person in charge of the prescribed burn) determines if the predicted weather matches what is required in the Prescribed Fire Burn Plan (a document that describes the project in detail, including goals, objectives, required weather parameters, volume and type of vegetation to be burned, maps, required personnel and equipment, etc.). The goal is a safe, clean burn with minimal smoke impacts, so particulars such as the altitude and aspect of the burn site and the dryness and makeup of the fuels are all compared with the weather forecast. If the predicted weather is favorable, the process of notifying cooperators and members of the public that a prescribed burn will take place begins. On the day of the burn, the Burn Boss will often request a “Spot” weather forecast from the NWS for the specific burn site to make sure that conditions are still good to go. The Spot forecast is explicit to the specific burn unit at that time, rather than for the larger fire weather zone. Because it uses current, site-specific weather observations and takes into account local terrain features and microclimates, the Spot forecast can be significantly different from the forecast for the fire weather zone that was issued the previous day. Usually, the Burn Boss receives the finished Spot weather forecast from the NWS about an hour after it is requested. Clearance to burn The State of Oregon requires that Smoke Management Rules be followed for the “prescribed burning of forest fuels for forest management purposes.” This is the law, and federal land management agencies must follow it like anyone else. The state also has a Smoke Management Plan, which is designed to protect air quality. In support of this effort, the Oregon Department of Forestry operates a Smoke Forecast Office, which is located in Salem. Just like the NWS, the state uses fire weather zones for its smoke forecasts and instructions. Every day between 2-3 pm during the spring and fall prescribed burning seasons, a smoke management forecast is issued for the following day. The forecast contains instructions specific to each fire weather zone. Based on the predicted “mixing height” (the height the smoke needs to rise above the ground before it disperses into the atmosphere) and the “transport wind flow” (the wind that blows the smoke out of the area), prescribed burning within a zone may have varying restrictions applied in order for the prescribed burn to meet air-quality standards. Restrictions might be placed on tonnage (the amount of material to be burned), spacing (distance between burn units), time, and distance to smoke- sensitive areas. If the forecast calls for no burning, or if it limits the amount of tonnage that can be burned, the FS/BLM can request an exception. Often an exception is requested because, from experience and local knowledge, the Burn Boss suspects that the smoke forecast may not accurately reflect actual conditions at the burn site. (After all, Salem isn’t exactly right around the corner.) Depending on the location of the unit, e.g., high elevation, distance to homes or recreation areas, etc., as well as the type and amount of vegetation being burned, it is sometimes possible to conduct a successful prescribed burn with no appreciable impact to air quality from smoke, even if the initial zone forecast did restrict burning. To request an exception, the FS/BLM Burn Boss calls the Smoke Forecaster by phone, provides a legal description of the project area, and describes the amount and type of vegetation to be burned. The Forecaster then focuses on the specific area and can grant permission to burn based on the current conditions at that site. Sometimes the Forecaster grants permission to proceed with a prescribed burn because the smoke forecast (which was produced the previous day) doesn’t match the actual conditions on the ground. The Burn Boss can also negotiate with the Forecaster to get permission to burn a portion of the unit or a lesser amount of material (fewer tons) while still meeting air-quality requirements. And sometimes, after talking with the Burn Boss, the Forecaster sticks with his initial determination and will not grant permission to burn based on air-quality concerns. The Smoke Forecasters are fully aware of the importance of prescribed burning as a land management tool and make every effort to not restrict prescribed burning unless it is necessary to maintain air quality. Air Stagnation Advisories (ASAs) During the winter months, ASAs may be issued by the NWS for the Rogue Valley. These advisories warn of weather conditions in which air pollutants get trapped in the valley and do not clear out as they typically would. This can result in serious air-quality issues in the valley. When an ASA is issued, residents are asked to limit their driving and the use of wood-burning stoves. However, most federal prescribed burning takes place outside of the Rogue Valley proper, and is usually at higher elevations. Therefore, an ASA does not necessarily constitute a ban for prescribed burning in or near the advisory area. While members of the public might express concern that the FS/BLM is burning during an ASA, it’s important for people to understand that an ASA is usually issued for the general public in the populated areas (typically in the valleys). During an ASA, our rules mandate that prescribed burning be closely controlled in such a manner that smoke from the burn will not further degrade air quality in the ASA area. Prescribed burning may be allowed if the smoke will vent away from or above the ASA area, so in these cases we rigorously check wind conditions to get it right. After all, we are residents of the Rogue Valley, too. Rob Budge • 541-618-2102 Deputy Fire Staff, Fuels Rogue River-Siskiyou National Forest NOTE: See online article, “Federal forecast predicts fewer wildfires in West this year.” Spot weather reports and burning early in the day can help keep smoke from moving down into valleys or residential areas. Photo by Sandy Shaffer.
