Wildfires are fires that start uncontrollably in natural areas like forests, grasslands and prairies. They can cause damage to natural resources, destroy homes and threaten the safety of the public and firefighters.
Most wildfires are caused by human actions. These include leaving a campfire unattended, burning debris, or improperly discarding cigarette butts.
Weather
The weather, especially during the spring and fall fire seasons, plays a crucial role in wildfires. It can help firefighters and land managers prepare for a high fire danger or provide red flag warnings to inform people to avoid certain areas, according to National Weather Service forecasters.
The most critical weather factor for wildfires is wind – the force of the wind dries out fuels, causing fires to spread and burn more intensely. The fire itself can also cause wind conditions to change and create storms, such as tornadoes and whirls.
Lightning, which ignites many forest and rangeland fires, is also closely linked to the weather. Gusty winds, which accompany thunderstorms, can increase the chance of a lightning strike, accelerating fire growth and making it easier for a fire to spread and catch fire crews off guard.
Another key factor is temperature – warmer temperatures make it harder to control fires because they require more water and fuel. Rising temperatures and drier weather are contributing to more frequent and severe fires.
Drier weather can lead to a faster spread of the mountain pine beetle and other insects that kill or weaken trees, leading to more wildfires. These factors are likely to increase in the future as climate change continues to impact weather patterns.
Fire weather can also be influenced by the amount of rain. Dry lightning is more likely to occur during a heat wave than during a drought, which can stoke the flames and accelerate their movement.
A study from Climate Central shows that climate change is increasing the number of days when fire weather occurs, which could make it more difficult to control fires and increase their impact on the environment.
The number of days with high fire weather risk has doubled between 1984 and 2015 in much of the western U.S., a trend that is expected to continue if greenhouse gas emissions remain high.
The fire danger is usually most severe during the early afternoon when temperatures are at their highest, wind speeds are strongest and relative humidity is lowest. During this time, rapid fire growth potential is most prevalent and firefighters rely on accurate forecasts to plan and manage their response.
Fuel
A fire's ability to burn depends on a complex set of factors. Among them are fuel moisture, chemical makeup and density.
Moisture is the primary factor determining flammability, but a fuel's size and density also influence how fast it ignites, spreads and burns. Lighter fuels, such as dry grass and dead leaves, can burn quickly, whereas heavy logs or stumps will take longer to ignite.
The moisture in fuels is influenced by the amount of water in the air, as well as the temperature of the air. Relative humidity, which is the rate at which air can hold water, varies as weather conditions change throughout a day or even within a single hour.
In general, fires tend to start and spread faster in low-moisture areas, such as valley bottoms or in the bottom of a lake, where the air is relatively cool. In high-moisture areas, such as a mountain or along a river, the air can be too humid for fire to break out, since the water in the air is more easily drawn into the fuels.
Another factor influencing fire spread is wind. Strong winds help a fire preheat unburned fuels around it, but can also carry burning embers away from the blaze to ignite spot fires.
As a result, it's important for firefighters to understand the types of fuel that they will be dealing with. They can then use this information to guide their tactics during a fire.
Firefighters can also use this knowledge to assess the potential impact of different fire treatments. They can then decide which treatment would be best for a given situation.
The type of fuel that a wildfire will use can make all the difference in its behavior, so knowing this information is crucial for preventing disasters and for reducing damage to property and natural resources.
Forest fuels include everything from the "duff" or organic parts of dirt and underground roots to standing snags, large fallen logs and other dead trees. They are grouped into three layers: ground fuels, surface fuels and aerial or crown fuels. firescout
Sparks
A wildfire needs three things to ignite and spread: fuel, heat and oxygen. The fuel is any kind of flammable material, like grasses or wood. When heated to their flash point, these materials emit vapors that mix with oxygen in the air and ignite.
Sparks are hot metallic particles that fly away from the source of the fire. They can be produced by a variety of sources, including power lines and vehicles.
Embers are another type of spark that can ignite a fire when carried by the wind. They can move long distances in the air, so they can start fires in spots far from where they first started.
Vehicles and equipment are other common ignition sources, especially when drought conditions are severe. Cars and trucks with a faulty engine, tires that scrape the asphalt, or even engines that catch fire after an accident can all start a wildfire when the grass next to a road is dry.
Lightning, another major ignition source, can also cause fires in the wildland areas where it occurs. Lightning strikes send sparks to the ground, igniting dry fuel like sawdust and leaves.
Equipment use and maintenance can be a great way to reduce the risk of a sparking fire, so make sure your tractors, chainsaws, mowers and other portable gasoline-powered equipment are properly maintained and in good condition. Always check to ensure that spark arrestors are in good working order and aren't covered with carbon buildup.
Welding and grinding operations are also a potential source of sparks, so make sure to wear a welding helmet, leather protective gloves, and high-necked, low-flammability clothing when you're using these tools. You should also make sure your exhaust system is in good working order and that your fuel is the proper grade for your type of work.
Fireworks are another popular ignition source, but they can be dangerous if they're not used properly. Fireworks are regulated in Wisconsin, so check with local law enforcement agencies to find out about the restrictions in your area.
Conditions
Wildfires cause damage to forests, homes and communities. They burn down trees, shrubs, grasses and other vegetation, leaving behind ash and smoke that can cause respiratory problems for people. In addition, a wildfire can kill wildlife and destroy the habitats they need to survive.
Lightning is the most common non-human cause of wildfires, but other factors can also lead to fire. For example, volcanic eruptions can ignite lava and ash, while steep slopes can make a fire spread faster and more efficiently.
Climate change has aggravated the problem by prolonging droughts and driving temperatures higher. In turn, these conditions have dried out vegetation, which increases the number and severity of fires.
Vegetation is the main source of fuel for wildfires. Trees and shrubs produce more heat and blaze more quickly than grasses, which are less flammable.
Slopes and aspect (the direction the land faces) also affect the intensity of wildfires. South- and west-facing slopes have drier fuels than north- and east-facing slopes.
Another condition that can speed up the spread of a wildfire is wind. As the ambient wind moves uphill, it preheats unburned fuels, which makes them more flammable.
Humans can also contribute to the conditions that cause wildfires by trimming and burning trees, burning down buildings or removing flammable materials from their properties. They also increase the risk of wildfires by building homes and other structures close to forest areas.
Increasingly, humans are converting more land to farming and ranching. This conversion is resulting in the burning of more forest areas and increasing the number of wildfires, according to a new study published in Science.
The study found that, on average, human-caused fires were six times larger than those caused by lightning strikes, which in turn killed about three times as many trees.
These fast-moving, ferocious fires are capable of destroying wide-open meadows that animals such as deer and meadowlarks like to roam in. They can also destroy habitats that wildlife depends on, causing loss of life and economic damage.
Globally, the number of days where wildfires are likely to occur has risen as a result of climate change, according to the National Center for Atmospheric Research. This is a serious problem for the world’s wildlife and ecosystems.Weather Plays a Crucial Role in Wildfiresd
