Wildfire statistics for Missouri confirm how different wildfire is here compared to wildfire in the national parks and forests of the Northern Rockies.
Wildfire statistics for Missouri are kept by two agencies: the National Interagency Fire Center (NIFC), and the Missouri Department of Conservation (MDC). Let’s look at the NIFC data first.
Most wildland fire in Missouri is either started by humans or requires human intervention to spread significantly (see previous post). The NIFC data calls fires that were not prescribed “wildland.” Figure 1 shows the number of square miles burned by wildland fire (blue) and prescribed fire (red). I have dropped linear regression trend lines on the data (the dashed lines).
You can see that the number of acres burned in wildland fires has varied widely, from a minimum of 1,660 in 2013 to a maximum of 55,395 in 2011. The number of acres burned in prescribed fires has also varied widely, from a minimum of 6 in 2003 to a maximum of 95,268 in 2009. In contrast to much of the rest of the country, Missouri does not appear to be experiencing an increase over time in the number of acres that were burned in wildland fires – the trend is basically flat. For acres burned in prescribed fires, however, there was a significant increase until 2011, and since then the number of acres has slowly decreased. Over the 13 years with data, wildland fires burned an average of 24,209 acres per year, and prescribed fires burned an average of 38,078 acres per year. Thus, for every 2 acres burned by wildland fires, more than 3 were burned by prescribed fires.
The number of acres burned by wildfire in Missouri is somewhat lower than in many western states. This year, 4 wildfires burning in Wyoming each burned more than 20,000 acres, and the Maple Fire by itself burned 45,425 acres. In California this year, the Soberanes Fire burned 132,127 acres.
The fire data from the NIFC includes fires managed by federal agencies (in Missouri principally the National Park Service, the U.S. Fish and Wildlife Service, and the U.S.Forest Service). It also includes a subset of fires managed by state agencies, although what is included in the subset is not clear. MDC’s data seems to come from fire reports by local and regional fire departments. Those reports appear to be voluntary, and I couldn’t find any guidance about what the local departments file reports on. I did notice that the data included reports from departments that were the primary responders to fires, and from departments that were assisting responders to fires. Thus, there could be duplication in the data, as well as inconsistencies from year-to-year in the participating departments. It is also unclear what lands are included (state lands? private lands? developed lands? undeveloped lands?). For these reasons, I can’t use MDC’s data to indicate either the absolute number of fires in Missouri, nor their trend over time in acreage burned. The data do indicate the cause of the fires. Despite the possible inconsistencies in the data, it seems to me that they can be used to give a rough indication of the causes of fire in Missouri, especially if summed over a number of years.
Figure 2 shows the percentage of Missouri fire from each cause from 2006-2015. The largest category is Unknown. After that, however, the largest category is Debris. This is where somebody burns something – a pile of brush they cleared from their land, some construction waste, etc. – and the fire escapes. The next largest category is Arson. Lightning accounts for only 1% of the fires counted by MDC. Dry lightning is common in the West (lightning from a thunderstorm that drops no rain), and it accounts for about 2/3 of western wildfires. It is rare in Missouri, however. In addition, Missouri’s overall climate is wetter and more humid. A lightning strike may cause a single tree to burn, but it rarely spreads into a significant fire.
I wish that the Missouri Department of Conservation’s data included a description of what the data counts. Despite repeated attempts, the director of their fire program and I have been unable to connect with each other, so I haven’t been able to clarify it.
The next post will explore why western wildfires have become larger and fiercer in recent years.
InciWeb Incident Information System. This is a data portal. To find wildfires in Wyoming, I selected “Wyoming” in the “Select a State” data field, and clicked “Go.” Data viewed 10/31/2016 at http://inciweb.nwcg.gov.
Missouri Department of Conservation. Wildfire Data Search. Data downloaded 10/31/2016 from http://mdc7.mdc.mo.gov/applications/FireReporting/Report.aspx.
National Interagency Fire Center. Statistics > Historical Year-End Fire Statistics by State. Data downloaded 10/31/2016 from https://www.nifc.gov/fireInfo/fireInfo_statistics.html.