California is known for its beaches, but it is also becoming more famous for its fire weather. This is when high temperatures combine with strong winds and low humidity to make the landscape ready to burn. You've heard so much about wildfires over the years. A new analysis suggests that fire weather is increasing due to climate change.
It's more than hot. It's more than just being hot. Kaitlyn Weber, a Climate Central data analyst, said that all of these conditions are occurring simultaneously. The analysis was published by Climate Central, a non-profit news organization. It is clear that there has been an increase in fire weather days since the 1970s, across most of the western United States.
Weber examined data from 225 weather stations in 17 western states dating back to 1973. He looked at wind speeds and temperature as the main factors that can cause catastrophic fires. Low humidity and high temperatures can dry out vegetation, creating dry fuels. This allows one spark to ignite a wildfire that swift winds can push across the landscape at incredible speed. For example, the Camp Fire of 2018 erupted so fast that it overtook Paradise, killing 86 people. Many of them were trying to escape from town in their cars.
The maps below show the percentage change in annual day when the three variables were above the thresholds Weber used to analyze them. (Bluer colors mean fewer days, redder colors mean more days.) Wind, for example, means speeds exceeding 15 miles an hour and temperatures above 45 to 55 degrees Fahrenheit depending on the season.
It's no surprise that the southwest has become much hotter than it used to be. However, you will also notice that the southwest is experiencing more windy days. This is because an ignition can quickly turn into a fast, intense fireball.
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The map above visualizes when these three variablestemperature, humidity, and windcombined to produce fire weather days, shown as percent change since 1973. Every part of Colorado has seen at least 100 percent more fire-weather days. Texas is also looking grim, with the southern tip experiencing a 284 per cent increase in fire weather days. Central California is also in trouble with a 269 per cent increase in fire days. Weber says that the Southwest was truly coming out on top. We are seeing parts of Oklahoma, Kansas, and other places that we might not normally think of as fires.
If you're wondering why we don't hear of catastrophic fires in the plains state like in California, Oregon and Colorado, it is because fire weather simply means that the conditions are right for a fire to occur. Weber says that we are not talking about the incendiary of fires. Weber says that we are referring to the amount of days each year when the weather elements prime the terrain for high-risk fires that can be really dangerous to fight and even more difficult to combat.
Wildfires can also be exacerbated by atmospheric conditions. For example, land management decisions in California or Oregon play a part. These areas are covered with forests that were once healthy and regularly burnt. Lightning would set off a small fire, which ate through the brush, allowing for new growth while keeping many old trees alive. Native Americans used to set fires for strategic resets of ecosystems. Although the landscape was very hot, it also burned much less intensely because flammable brush wasn't allowed to accumulate between burns.
In the last century, however, land managers have adopted a different approach. They use fire suppression to immediately extinguish any encroachment on residential areas. This has allowed for more fuel and dry vegetation to build up. People are setting fires more often, from accidental cigarette smokes or the malfunctioning of electrical infrastructures.
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This is why California fires are more destructive than Oklahoma or Kansas. There's more forest, with more fuel, and more people in danger. Land managers in the west need to use more controlled burns to adapt. This will allow them to do the same brush-clearing work as smaller, frequent wildfires.
Some seemingly contradictory seasonal changes have also been caused by climate change. A warmer atmosphere holds more water so the amount of precipitation could increase, but the wet season length is shrinking. Rains in California typically arrive around October and last until March. They are now arriving later in the year. Ruby Leung, a climate scientist at the Pacific Northwest National Laboratory, said that the dry season will become the normal wet. The fire season will get longer if we look at climate models that project into the future.
This is what firefighters are seeing already. California's biggest fires used to occur in autumn. This was before the arrival of the seasonal rains. The landscape was extremely dry from a half-year without water. This was due to the strong seasonal winds that could cause wildfires. Because the rainy season has been so short, and the landscape has less time to dry out, fire season now comes earlier. We are now seeing fires grow larger and more frequently than we used to, Issac, chief of communications for California Department of Forestry and Fire Protection, stated earlier this month. These dry conditions are a direct result of climate change, so August rolls around and July rolls around.
Oregon has also been suffering from increasingly devastating wildfires in recent years, due to an increase in fire days. Weber believes that things will get worse unless global warming slows down. She says that we can expect more fire weather days as the climate warms. There is no easy way around this, no matter what we do. It's best to just accept it as it is.
This story first appeared on wired.com
