A large majority of areas on the west coast of the United States have experienced a wildfire season like no other this year. California, Oregon and Washington were the most impacted states with millions of acres burned in many forested regions.

This project will feature information on the hardest hit places and interviews from wildfire experts.

The cause that sparked most of the wildfires in California stemmed from a pyrotechnic device at a gender-reveal party on September 5.

The device ignited grass at El Dorado Ranch Park and caused several other fires to burn out of control throughout the state during September.

Maps of largest state wildfires

These three maps show where each of the biggest wildfires happened in their respective states.

Began as 38 separate fires before merging into California’s largest recorded wildfire. 935 structures were destroyed and five structures were damaged.

This wildfire was caused by lightning and merged with the Beachie Creek fire on September 8. 280 structures were destroyed and 10 injuries were suffered. 264 resident homes were lost in Detroit, Oregon.

This wildfire in Douglas County, Washington spread quickly due to strong winds and low relative humidity. Multiple structures were lost, but no injuries or deaths have been reported.

Images from Jessica Christian, San Francisco Chronicle photojournalist

These photos were taken in San Francisco, California on September 9. The hue of the dark orange skies were caused by a combination of smoke from various wildfires.
Link to Jessica Christian's tweet

Paul Hessburg - Professor of Environmental and Forest Sciences at University of Washington

Paul Hessberg

When are wildfires most likely to occur?

In the northern hemisphere, the wildfire season is the dry summer season. However, wildfires are occurring earlier in spring and later in summer with climatic warming. California now has a nearly year-round fire season; a change in recent decades.

Why do wildfires typically happen on the west coast of the U.S. and Canada?

Across western North America (wNA), forests grow where the snow persists in winter. As the climate has warmed, winter snowpack has declined, springs are coming earlier, winters are warmer, there are more rain-on-snow events that eliminate the snowpack much earlier, and fuels are curing out earlier. This leads to longer fire seasons and a greater likelihood of burning when an ignition occurs. Many years are also windier, and recent work shows that winds will continue to increase in intensity throughout wNA for years to come.

How do they impact the environment and climate change?

In Canada, wildfire emissions exceeded CO2 contributions from all other sections in 2017 and 2018. Wildfire smoke contributes many greenhouse gases to the atmosphere that can last quite a long time. For example, between 65% and 80% of CO2 released into the atmosphere dissolves into the ocean over a period of 20–200 years. Once in the atmosphere, the remaining CO2 stays in the atmosphere to affect our climate for many years.

What is most concerning about the current wildfire season?

For many it is the loss of beloved forests. Many of us live here because of the vast forests and the recreational and aesthetic experiences they afford us. Wildfires are also deeply affecting native species as their habitats decrease in size and abundance. People strongly connect with the western lifestyle, and our forests and big undeveloped landscapes are a part of that.

Marissa Baker - Professor of Environmental and Occupational Health Sciences at University of Washington

Marissa Baker

What risks happen when firefighters battle large wildfires?

What dangers do they face surrounding COVID-19?

Nick Bond - Washington State climatologist and Atmospheric Sciences professor at University of Washington

Nicholas Bond

What impact do wildfires have on climate overall?

What weather trends have been seen over the past few wildfire seasons? (Within Pacific Northwest)

Are these current wildfires more severe than past in terms of weather?

Edward Avol - Professor of Clinical Medicine and Division Chief of Environmental Health at University of Southern California

Edward Avol

What effects do wildfires have on air quality? Air pollution?

Have these current wildfires been worse than past in terms of smoke?

What health effects do wildfires have on humans?

What preventive measures can be taken to lessen the impact of wildfires on human health and air pollution?

High-risk wildfire area in Toronto

Cedarvale Ravine – Toronto, Ontario, Canada

Cedarvale Ravine spans 7.2 kilometres in the area of Humewood-Cedarvale in Toronto. It runs through the Forest Hill neighbourhood and includes a long walking trail surrounded by forestry. A park also exists close to the Beltline Trail to the north and Nordheimer Ravine to the south, which forms a large trail system; a large residential area makes up the rest. If a wildfire ever occurred nearby, it could easily spread quickly leading to damage in Cedarvale Park and Ravine and consume many homes in the process.

It is important that everyone educates themselves on what wildfires are and the destruction that they can cause.

Evacuation plans are also vital because wildfires can generate widespread panic. Although certain environments are more prone to experiencing wildfires than others, it is key that everyone takes the appropriate steps to prepare for an event of such magnitude.