Fall frost enhances fire weather concerns
By Jared Shelton News-Press NOW meteorologist
Above-average temperatures held a firm grip on the Central Plains through the first half of October, with many afternoons reaching the 80s and even 90s across Northwest Missouri and Northeast Kansas.
St. Joseph set a daily record high of 96 degrees on Oct. 5, conditions more suited for an August heat wave rather than the second month of meteorological fall.
As if just in time, the pendulum swung in the opposite direction this week, as Canadian air brought a chill to the air that stuck around for a few days. Temperatures across the Mid-Missouri River Valley went from below normal to below freezing early Wednesday morning, marking the first frost of the season. While some locations dipped just below 32 degrees, Rosecrans Airport tied a daily record low of 26 degrees for St. Joseph around daybreak, a mere 10 days after the record-setting high earlier this month.
While cold snaps this time of year do become more frequent, there are still plenty of mild days ahead before winter sets in. Even so, the damage is already done when it comes to deciduous vegetation, as Wednesday’s freeze brought an official end to the growing season.
The first few frosts of fall can ironically enhance fire weather concerns, as dead grasses, shrubs and trees can provide ample fuel for spreading fires. Gusty winds and dry air, which often accompany low-pressure systems as they push across the plains this time of year, can rapidly dry dead vegetation leftover from recent frosts, resulting in critical fire weather conditions. Unlike parts of the Intermountain West where wildfire season peaks in the summertime, the Great Plains and Midwest are often most susceptible for out-of-control fires in early spring and mid to late fall when most vegetation is no longer green and snowfall has yet to moisten soils and dead tinder.
Worsening drought conditions are also enhancing fire weather concerns across the Mid-Missouri River Valley, a triple threat when combined with the post-freeze die-off, and dry windy days. All the more reason to respect Red Flag Warnings, by choosing to burn on calmer days when conditions are less conducive for rapidly spreading grass and brush fires.
