Fire is used for many reasons across Kansas for positive results. However, fires that are uncontrolled can have very negative impacts, including property damage and personal injury. When these fires, often called wild land fires or wildfires, occur fire departments are called upon to extinguish them. Unfortunately, when weather conditions and fuels allow for ideal burning environments using prescribed fire, conditions are also sufficient for wildfires. This article focuses on analyzing wildfires of 2014 and the weather conditions that occurred near the time of the fires.
Kansas Fire Incident Reporting System (KFIRS) provides a method of submitting and archiving calls/incidents by fire departments. Incidents can be classified by type (structure fire, car accidents, and grass/vegetation/wildland fires) with additional descriptive details if the departments decide to include them. This archived data is an excellent resource for analysis of different influencing trends, anomalies, and various other impacts on different incidents, including wildfires.
Of the eleven years of recorded KFIRS data, 2014 had both the most land area burned (187,500 acres) and the highest number of reported fires (8,075) in a year. In both land area and number, fires followed the typical curve of the previous 10 years, with a peak during the spring months of March and April (see charts below).
This trend of spring wildfires coincides very well with prescribed burning season. Early spring is typically characterized by dead/cured fuels, warming temperatures, low relative humidity, and little precipitation. Often, if the late fall and winter are below normal in precipitation and/or the region is in a drought, these spring conditions are enhanced – providing explosive conditions for fire growth.
This was the case entering 2014. However, conditions were worsened by an increased fuel load from late summer rains of 2013 that brought some relief to the prolonged drought which peaked in 2012.These combined factors led to a peak of 156,600 acres burning in March/April 2014 alone. Of the 61 days possible in March and April, almost half (29) had more than 1000 acres burned statewide each day. Two days (Jan. 26 and Feb. 19) occurred outside of these months. Below, the March/April calendar with red days were those in which more than 1000 acres statewide were burned. Cold frontal passages throughout the period are marked on their associated day.
On days with more than 1,000 acres burned, weather data from the average start time in the central county of the fire activity were taken. This data consisted of Remote Automated Weather Stations (RAWS), Automated Surface Observing Stations (ASOS), Automated Weather Observing System (AWOS), and Kansas Mesonet (mesonet.ksu.edu) hourly data observations. Using relative humidity (RH), temperature, and wind speed observations, each location was analyzed according to its proximity to a frontal boundary. Categories were classified “Frontal Passage” if there was a frontal boundary at the focus of fire activity location and time, “Pre-Frontal” or “Post-Frontal” when it was located within 100 miles ahead/behind a front, “No frontal boundary at time of fire” if no boundary was within 100 miles at the time, or “No frontal boundary” when no frontal boundary was within 100 miles to center 24 hours before/after average ignition.
National Weather Service (NWS) Topeka (TOP) will typically issue a Red Flag Warnings (RFW) on days of critical fire danger. These RFWs are issued when fuels are cured or dead -- combined with winds greater than 15mph and RH less than 20% -- forecasted for three or more hours. A RFW issuance warns the public of fire risk and is used to create awareness of dangers involved.
Applications of a RFW include helping fire managers determine whether to put fire on the ground during a prescribed burn, helping individuals decide on participation of outdoor activities that include fire/sparks (campfires, shooting guns), and helping fire departments evaluate required staffing needs. These thresholds provide an excellent method to evaluate volatile weather conditions. However, criteria varies from region to region depending on the NWS office, and since the majority of fire foci were in/around the Flint Hills, only TOP RFW criteria were considered.
From 2014 results, during any of the weather periods considered, none of them reach RFW criteria. While some (Frontal boundary – wind, Post-frontal – RH) reach individual criteria (red shaded values in the table), the combination is required to issue a RFW which heightens public/manager risk awareness.
2014 was a record year in both land burned and number of fires. With the majority of fires/acreage occurring on non-RFW days, some additional research is required to evaluate why these fires are happening. Many possibilities exist, including: the need for better/increased thoroughness of reporting of cause, size, and circumstance of each wildfire; higher resolution weather data; social aspects of prescribed burning; evaluation of null events (no fires) on RFW days; and implications of public/manager decisions based off weather data and their subsequent results.
The analysis done for 2014 was meant to organize a scientific approach to compiling a database of correlated weather and wildfire data never done before. In the coming months, more research will be done using the other 10 years with available data to develop a climatology of fire weather conditions and to determine the anomalies and patterns in Kansas.
For further reading on this research, see the 2014 KFIRS report:
Christopher “Chip” Redmond, Weather Data Library
Mary Knapp, Weather Data Library