Today, it rained. The pall of smoke that had been hanging over my hometown for the past two weeks dissipated, and I feel newly zingy. I was thinking that this was something to write about, but wondered what I could write that would be of interest, especially since the entire meteorology and ecology of wild fires is somewhat beyond me.
But, upon signing on, I saw that there was some type of collective interest in the processes of the fall. I decided this was a sign, and decided that I would describe a little bit about what a fire season ending event is like, since it is characteristic of the autumn where I live. Of course, this is not meant to be exhaustive or scientific, and some of it may be specific to what I am used to.
One of the first things to explain is "fire season". This has caused some confusion when I mention wildfires to people who don't live in the Rocky Mountains, because to them it seems like a dire natural disaster, an emergency in need of immediate insistence. Fire season is a season, a regularly scheduled event that happens every year. Some fire seasons can be disasters, with lives and property destroyed, but many of them burn in wilderness for a long time, and burn tens of thousand of acres, without immediately impacting people. And even fires in isolated places are attended and controlled, even when they are allowed to burn. However, for the most part, wildfires are not treated as an emergency anymore than flatulence or menstruation requires an emergency room visit.
The previous winter, of 2010-2011, was a very wet winter, although not a terribly cold one. At some points in the Bitterroot Valley, the snowpack was over 300% of normal. Snow takes a lot of heat to melt, and at high elevations, the temperature goes below freezing at night well into June. Because of this, much of the mountains stay moist and fairly fire-proof into early July, if not later.
Of course, if there is a bad lightning storm, or someone commits arson, or just because events lie on a bell curve, the fire season can start much earlier. But this year, through the middle of August, there was no major fires. I assured myself and others that we were too close to the September rains (and frosts, and snows) to worry about a major fire event. And then one day...dirty orange clouds drifted out of the western sky. And from that date, things rapidly got worse. The snow lasts a long time, but once it is gone, there is no moisture, and the mountains quickly become dry and ready to burn. It seems improbable that mountains can go from being capped with snow on July 15th to conflagrations on August 15th, but such a thing is common enough.
Wildfires are all different. The worst wildfire this year came from the east, on the Sapphire Mountains. The Sapphires are not really "forested" in the way that some may think, but are more a mosaic between meadows, scrub and ragged stands of pine trees. Due to the fact that it was foliage and grass as much as wood that was burning, the fires gave off a thick white smoke that then, due to a temperature inversion, fell into our valley and stayed there for two weeks. The fire itself was not a threat, but the smoke was a great annoyance, and after enough time, even "safe" amounts of smoke degrade a person's enjoyment of life.
The temperatures in September, at least the day time temperatures, were also higher than they usually are, and it seemed for a while that we would be in the middle of a suffocating heat with mind-numbing smoke until possibly mid-October. It was not a welcome prospect.
And so that brings us to today. Today started out cloudy, and windy. The clouds help, the wind does not, since it can spread fire quickly. However, around 3 PM, a few drops of rain begin to fall. I went for a bicycle ride, since the lack of smoke and coolness in the air more than off-set the few drops of rain that were falling on me. As I rode, the rain made the last few weeks of oppressive smoke and heat seem to be quickly a distant memory. I quickly remembered how fun the countryside could be to view on a brisk autumn day. The rain continued to fall, lightly but steadily. At the least, my psychological fire season is over.
Whether today marks the end of the objective fire season remains to be seen. Weather and fire being what they are, it is possible that the weather could clear up and warm up, and we could have two more weeks where the fire becomes even worse and spreads further. Or today's rain, which was only a fraction of an inch, together with the cooler temperatures, could extinguish the fires. More likely is somewhere in-between: that today's rain and damp marks a period when the fires will gradually fade away.
A fire season ending event can be many different things, just as a fire season can be. It can be a foot of snow dropping seemingly out of nowhere in early September, extinguishing ravaging fires in a single dramatic day, or it can be a series of rain and damp in mid-October that gradually ends creeping brush fires. In any case, in Montana, where fire season happens every year, a fire season ending event is something that people look forward to, somewhat desperately, and sometimes, such as today, a light rain that seems unremarkable is a sign of relief from the smokes of summer, and into the cool of autumn.