Yesterday I picked up my mail and opened the agenda for our upcoming HOA Board meeting. There in bold letters was the central item for discussion and decision – “Deepening Drought to Force Water Conservation and Landscape Maintenance Changes.” I guess I knew this was coming but I felt something was missing. What about discussing the impact of the drought on the growing threat of wildfire and what we are going to do about that? I’m no expert, but common sense tells me that the lack of water means a greater amount of dry fuel and in turn, more severe wildfires! I vividly recall the difference between a campfire burning with wet wood and one with dry wood. So I took the time to call a local fire behavior expert, Mr. Sandy Munns and get his opinion on the effect of the drought on the danger of wildfire. Mr. Munns is currently the Fire Training Program Coordinator at Truckee Meadows Community College. He has years of experience fighting wildland fire and understands the effect of the environment on the way a fire burns. And he sure had a lot to say!
He explained that drought is all about water. Interestingly, so is wildland fire. The amount of water in the dead and living vegetation is called fuel moisture and determines how hot the fire will burn. When fuel burns, some of the heat produced is used to evaporate the fuel moisture. The wetter the fuel the more heat is taken up to evaporate that water. So fuel moisture can act like a brake and the higher it is the more it can just slow or calm things down. We see this in the size of the flames. Low fuel moisture means big flames. In contrast, if fuel moisture is very high, the fire may not even ignite.
Drought has several impacts on fuel moisture. First, while fine dead fuels like grass and weeds may change moisture content in as little as 1 hour, large fuels like limbs and logs, can take more than a month. During a drought, these large fuels dry out more quickly and, during a wildfire, produce bigger flames. Second, living foliage on brush and trees typically has very high fuel moisture and generally will be less flammable. During a drought, the moisture of live foliage gets so low it burns like dead fuel, also causing bigger flames.
Mr. Munns went on to explain that bigger flames lead to wicked and unpredictable fire behavior making fires difficult or impossible to control. Bigger, hotter flames also spread into the tops of brush and trees, usually killing them and leaving little behind. In other words, drought creates hotter, more severe fires that advance rapidly. Drier, hotter fires also increase the amount of embers that can start fires at a considerable distance from the main flame front. During a drought, the fuels that embers land in are drier, and more likely to ignite. This increases the risk of fires starting, particularly in and around structures. University of Nevada Cooperative Extension’s Living With Fire Program has a great publication to help you learn more about embers. Click here to download a copy of Be Ember Aware!
I imagine that the lack of snow and rain helps explain the recent fires outside of what we normally think of as “fire season”. Some examples are the Caughlin Fire in November, 2011 in Reno, the Washoe Drive Fire in January 2012 near Carson City, and the Round Fire near Bridgeport, CA fire just this week. Mr. Munns told me that damaging fires have burned every month of the year in the Great Basin, particularly during drought years. Mr. Munns concluded by emphasizing that preparing homes for fire is always necessary, but it is even more important, year round during a drought. Since it is an issue of great concern to the firefighting community, it should also be for my community.
Now I have a better understanding that drought causes hotter fires, allows the fire to spread rapidly and into the tops of brush and trees, and allows fires to burn every month of the year, even outside the ‘typical’ fire season. Drought increases the likelihood of severe fires causing more damage to not only the environment, but also to the homes right here where I live, in the wildland-urban interface.
I can tell you that Mr. Munns got my attention and painted a pretty scary picture. I read somewhere that to convince people of their vulnerability and stimulate action the threat of wildfire must be on the agenda; every agenda. I can assure you that when the HOA board meets to talk about the drought in a few days, a new item dealing with the wildfire threat will also be on their agenda.