Windy, warm, and dry is a good recipe for wildfires, and that has been the norm for Montana this year. For example, from June 1 through September 4, Missoula received 2.07 inches of precipitation, less than half its average rainfall for that period. Most of those two inches fell by June 13, early in the fire season. The average daily temperature since June 1 has been 68.9°F, or 3.3°F higher than normal.
Cumulative precipitation in 2017 since June 1 for Missoula, MT (red) compared to average (blue).
The total acreage burned according to Inciweb is a little over 1 million acres. Wildfires are common in western states, but this has been a particularly bad year. The area burned is about three times the size of Wayne County, OH.
Size comparison between Wayne County, Ohio, Rhode Island land area, and the 2017 burned area in Montana as of 11 Sep 2017.
The Rice Ridge fire is one of the largest fires in Montana right now, with 135,355 acres burned as of Monday morning. According to Inciweb, It is 8% contained and has 891 personnel devoted to it. This fire has also been long-lasting; it began back on July 24th from a lightning strike. Missoula is the nearest city, but the communities of Seeley Lake and Lincoln are much closer to the fire. Officials in Lincoln, MT have been making evacuation and fire-fighting plans.
The Rice Ridge Fire as of 11 Sep 2017. Darker red indicates more intense heat. Yellow areas are under evacuation warnings, and the dashed yellow line is the “no drones” perimeter. (Adapted from https://inciweb.nwcg.gov/incident/5414/.)
Glacier National Park, already with over 16,000 acres burned from the Sprague Fire and the Adair Ridge Fire, added one more active fire to the list on Saturday when a human-caused fire over the border in Canada spread into the northwest corner of the park. The Elder Creek fire has burned 211 acres in the USA so far, but it is considered low priority given its remote location. The Park recently lost the historic Sperry Park Chalet, built in 1914, to the flames. With warm, dry, windy conditions expected to continue in the short-term, the fire damage for Montana and other western states is likely to increase.
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Weather data from the National Centers for Environmental Information (https://www.ncdc.noaa.gov)
How does the insect damage affect these fires in Montana? Visiting national parks across CO, over the last couple of years, I’ve noticed huge swaths of dead conifer forests (particularly, almost the entire western slope of Rocky Mountain NP, on the descent westward along Trail Ridge Road). Are the MT forests equally devastated? Another aspect of climate change which requires mention, alongside sporadic and changeable rainfall patterns.
Hi Bill, thanks for the comment. This question about whether insect damage makes fires worse is being actively researched. Montana has experienced heavy infestation from insects recently, similar to Colorado. However, the scientific studies I’ve seen addressing this issue have not found a any connection between increased insect activity and increased fire activity. The data seem to indicate that the difference between live trees holding needles and dead trees with needles on the ground is not great enough to matter in comparison to other factors like a) number of trees, b) topography, and c) weather conditions. The change in climate, on the other hand, is strongly implicated as the cause for the increase in fire activity. I found this surprising when I first heard the data about a year ago, but the biogeographers are confident in their data.
Check out these sources for more details:
Hart et al. 2015
Andrus et al. 2017
Thank you! That is really counterintuitive, but I guess it, sort of, makes sense when you look at the low density of vertical logs in these tree-dead forests. You would have to look at ignition temps for green needles and their propensity to blow downwind vs. the dead trees and their lower density of tinder. Has anyone attempted to correlate all of this with Forest Service and NPS forest management practices? We used to hear a lot about how the urge to fight “all” fires made the ensuing ones much worse as a result of interrupting natural forest lifecycles. How well do we know the extent of forest fires prior to the satellite age? Certainly, our knowledge of fire extent is far better now than it was before both real-time satellite imaging and the massive human encroachment upon the forests of the West. Either way, human activity is implicated, but we may be seeing some level of increased reporting bias alongside that trend, too, since our baseline database is so much deeper now than it ever has been.
Looking at your second question first, Bill, yes I think that data issue sets a big limit on our ability to compare periods. We can use tree cores as decent enough proxies to at least address such questions — such as the observation that infrequent, high severity fires were common in fir-spruce forests even before fire suppression. It’s the mid and lower montane forests (e.g., ponderosa pine forests) that have really been changed by human practices. With that said, all of the papers I’ve read about trends in fire area or severity (like Dennison et al. (2014) ) limit their scope to the early 1980s and onward. Today, the forest service is experimenting with thinning and prescribed burns, but on private land and near communities, fire suppression is still normal (and for understandable reasons). With no satellite data before the 1980s, though, I’m not sure how much we can say about the impact of the government agencies’ change in policy — and I don’t have a good study in mind (or after a quick search) that really addresses that question head-on.
Thanks for taking so much time to answer my questions!