Iowa communities and counties have initiated burning restrictions or bans in the past few weeks. Little snow accumulation during a mild winter followed by dry, windy and unseasonably warm spring temperatures have created dangerous conditions for field and ditch burning this spring.
Key factors in conducting a safe burn include monitoring wind direction and wind speed, temperature, and relative humidity. Jesse Randall, Iowa State University Extension forester, outlines how to control an open burn and he also explains the situation when it's not advisable for you to conduct a burn.
How to control an open burn; keep flames and smoke where they should be
When weather conditions are advisable for open burning, taking safety precautions will help ensure flames and smoke stay where they should.
"A fire stop should be created around the entire perimeter of the area where open burning is to be conducted," says Randall. Fire stops can be created by maintaining a mowed green area of 20 feet wide around the perimeter of the area to be burned or disking a 20 feet wide strip around the perimeter of the burn area.
"This time of year it is even more important to consider smoke management, as that is more of a risk than escaped fires in the spring when there are no crops in the field," Randall says. "Putting smoke over a road or into a home or barn can be devastating."
When not to burn—never burn without first checking the weather forecast
Do not burn when smoke will blow toward or linger over populated areas or major roads and highways. Winds should be between 5 to 15 mph for prairies and 20 to 25 mph for woodlots and savanna. Wind direction should be checked.
Never burn without first checking the National Fire Weather Forecast at http://www.srh.noaa.gov/ridge2/fire/. No burning should occur if the area is under a "fire weather watch" or "red flag warning." Burning should also not occur within 24 hours before or after a major frontal change as shifts in wind direction and speed create an unstable atmosphere.
Avoid burning during periods of drought. Relative humidity should be from 35% to 55% for prairies and 20% to 50% for forested areas.
Do not initiate burning early in the morning as relative humidity is the highest in the morning. Burns should begin after 9 a.m. Mixing height (height at which the smoke will mix with the atmosphere) peaks during mid to late afternoon.
Randall recommends contacting the local fire department to discuss plans to control fire spread and ask if they have any additional suggestions. Counties, municipalities and other areas have restrictions on when burning can occur or may require special burn permits. For more information about safely conducting a controlled fire, see the ISU Extension prescribed burn publication series available for download from the Online Store store.extension.iastate.edu/, search for prescribed burn. To learn what areas in Iowa currently have burn bans in place see http://www.dps.state.ia.us/fm/main/burnbans/index.shtml.