The 2015 wildfire season has definitely seen a different trend than past seasons. The change was not necessarily a massive overall national increase in fire, but where those fires occurred. For instance, in Colorado it has been a very tame season but by comparison the Pacific Northwest has seen a very busy fire season. This blog describes those changes, and suggests a data-driven approach to forest management while also adapting to wetter and drier conditions. Both of these issues by the way are due to climate change.
Climate Data Shows Jet Stream Blocks Due To Sea Ice Changes
Changes in sea ice modeling has shown how it has impacted the jet streams of both hemispheres of the planet. This in turn has caused changes in patterns of precipitation. Areas with less precipitation will have less soil moisture. Also, areas with lots of fuels have a higher chance to catch fire. The opposite is true for areas with higher precipitation events, again due to the jetstream changes we are seeing.
2015 has seen the combination of El Niño and higher Arctic Sea Ice melt, which has caused major “waves” in the jet stream. These waves are sending precipitation above the US west coast into Canada. Then they come back down into Eastern Montana on the Rocky Mountain Eastern Front Range. This video (https://www.youtube.com/watch?v=Lg91eowtfbw) explains how these jet stream “waves” are causing longer periods of local precipitation patterns. And due to these “longer waves” camping over those areas, they are causing longer times of either drought, high precipitation events, or just nice weather for those lucky regions.
Fire Data Shows Built-Up Fuels Are the Major Issue
To pile onto the massive changes in soil moisture, there is an even bigger problem leading to larger fires which is clearly human-caused: high fuels. For multiple decades starting in the 1960s and going to the 1990s, our national forest management policy has been to put out fires as soon as possible. This stopped the natural cycle of nature “getting a haircut” and thinning the forest. This led to escalated growth of younger, smaller trees which can cause flames to leapfrog into the upper tree canopy. Also, tree species usually low in concentration have increased where the tree canopy creates more shade. This creates even more dense forests and fuels.
In other areas the fire mitigation policy was to conduct prescribed burns to reduce fuel loads. This has been effective in some areas but detrimental in others, where natural species take years and years to grow and rapidly spreading invasive-growing species take their place creating more fuels (i.e. chapparal).
The United States actually has more trees than a century ago, even during this era of great human expansion and double the population. People hoping for reduction in greenhouse gases applaud this growth in forests, unfortunately adding more fuel for nature to fight fire with fire. An article from Buzzfeed that reviews raw NIFC Wildfire data shows fire statistics overall were not much higher nationally, and are following expected trends. However, it then points out how the concentration of fire in the Northwest was likely. This was due to legacy forest management issues causing higher fuels. The article is more pragmatic than holistically analyzed, but its point is fair. Basically it states that the higher chance of fire are due to low soil moisture. Also, combine that with higher fuels you get larger fires.
These Are Simple Stories – But Simple Visuals and Interesting Science Behind It Show a More Complex Picture.
Maybe the issue of increased wildfire was fuels alone. However, then the change in wildfire location would not be such a major difference. Mainly because this is a national forest management issue. It is clear the change in soil moisture from jet stream changes are a major cause in the pattern disruption. Now, it is true that the jet stream and sea ice data show more predictive indicators of precipitation. It also shows indicators for clouds, soil moisture, and sea ice. However, the wildfire data shows the lagging indicators as a result of the fire. This is shown especially where increased drought and higher fuels.
Bringing these two worlds together will hopefully help improve the overall wildfire models. It will also hopefully help with policy decisions both in forest management and addressing the changing climate. Wildland Fire Management approaches are slowly changing, balancing the movement of homes into the forests or WUI and allowing fires to burn where we can keep structural, public and firefighter safety at lower risk. Budgets to fight these fires are typically several billion dollars a year. They require several tens of thousands of people. Also, hundreds of aging and limited pieces of equipment to fight these events. Each event brings high risks and can run up costs totaling millions to multiple tens of millions to battle. Also, each bring ancillary impacts in air quality, safety, evacuations, commerce impacts, etc.
Which Now Begs the Question…
Are we too far behind in forest management policy to spend those monies on forest management suppression activities in pre-event situations where there is much less risk to structural, public, and firefighter safety? Then, there is the larger issue of adapting to or addressing trends of climate change. We are unfortunately not in to cross-stakeholder group alignment any time soon. The true question is can we move to data-driven policy and government decisions, and are the models clear and simple enough to help make changes to generations of infrastructure built on completely different societal approaches?