Weather forecasts help experts predict wildfire risks and plan responses
by Janie Yurechko -
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Weather forecasts help experts predict wildfire risks and plan responses

Weather data supports critical wildfire management from long-term planning to immediate tactical responses.

As the threat of wildfires increases, weather data can help emergency management experts gauge the potential of an outbreak. The data also supports incident commanders as they plan tactical responses to active fires. And developments in satellite remote sensing are making it possible to estimate vegetative coverage across wide and remote areas, promising another tool in the wildfire management toolbox.

Wildfire season all year round

Blazes tore through four million acres in the West Coast this year, marking another record-breaking year for wildfire activity in California. Five of the state’s six largest documented fires have occurred since August, and seventeen of the top 20 since 2006. As a chief from the state’s department of forestry and fire protection said: “Fire season is not a season anymore—it’s year-round.”

The trend isn’t limited to the West Coast. Wildfires burned nearly twice as much land per year between 2000 and 2018 in the United States than between 1985 and 1999, according to the Union of Concerned Scientists. And the situation could deteriorate. The non-profit established a “strong connection” between wildfires and climate change, which causes conditions to become hotter and drier. Another study found that “climate change has already facilitated conditions that are increasingly conducive to wildfire activity, and continued global warming will continue to intensify those conditions in the future.”

As the threat of wildfires has grown, population growth has pushed communities to build houses and structures closer to high-risk territories. Catastrophic losses have followed. Since 1980, the U.S. has suffered 18 billion-dollar fires, and today some 4.5 million homes are still at extreme risk of wildfire.

Reversing this trend and restoring public safety will take cooperation. Weather data can help.

Reading wildfire risks in weather forecasts

Weather conditions play a central role in gauging the risk of a wildfire—a science that stretches back decades. “Of the factors that affect the daily changes in fire danger, weather data is the most significant,” explains a handbook on the U.S. fire danger rating system from the National Wildfire Coordinating Group.

The key variables that experts consider are air temperature, humidity, and wind speed and direction, all of which impact fire danger and behavior. “Ask any wildland fire expert about the weather components that lead to difficult fire conditions, and the expert will reply with some combination of ‘hot, dry, and windy,’” wrote U.S. Forest Service experts and researchers in a paper.

It’s important to track temperature because a certain amount of heat is required for ignition and continued burning, according to material from Auburn University. Hotter fuel—grasses, needles, brush, and so on—burns more readily and quickly. Wind heightens the danger of wildfires by drying out fuels and supplying oxygen to flames. And fires tend to ignite more easily and burn more intensely at lower relative humidities.

In short, to accurately measure wildfire potential, experts require precise weather data. Forecasts that offer as much lead time as possible while maintaining accuracy can help specialists pinpoint at-risk communities, issue warnings, and develop strategies.

“In the emergency management sector resources are constrained,” said William Cromarty, a federal account executive at Spire Global with a background in emergency management. “Weather data allows an incident commander to prioritize resources and anticipate where to deploy support in advance, given you can never have 100% coverage.”

Should flames ignite, weather data can offer critical insight into a wildfire’s evolution and lifespan. Wind speed and direction are particularly impactful, influencing where and how far a fire might spread. And response teams consider wind speeds at different flight levels when planning how and when to deploy aerial assets like water bombers, helicopters, and drones.

Overall, weather data supports wildfire management from estimating seasonal risks to organizing immediate actions. “It’s one of the few unifying threads that span the gap of tactical and longer-term strategic planning,” said Cromarty.

Space data supports land management

Wildfire management teams need to know that the weather data they use is as precise as possible. Every extra degree of accuracy counts when so much is at stake. That’s why Spire recommends using weather forecasts powered by radio occultation data. It was recently identified as a top-five data type for reducing errors in forecasting.

Impacts of Various Data Types on Weather Forecast Accuracy

“Radio occultation offers ubiquitous and precise monitoring at a scale that you could never get from traditional observations,” said Mike Kay, engineering lead at Spire Weather.

Spire’s cubesatellites use this remote sensing technique to capture detailed temperature, humidity, and pressure information across the entire planet. Taking exact measurements around the world improves local forecasts since weather systems connect globally. It also ensures that emergency management professionals and search and rescue teams have highly detailed forecasting across their operational regions, no matter how remote.

Temperature (2m AGL) and Relative Humidity (2m AGL)

ADS-B Data and Wind Speed & ADS-B Data and Weather Radar

“Spire’s data offers an incident commander the ability to not only monitor localized weather conditions on location but also track the presence of local aviation assets via ADS-B in the affected zone for added situational awareness,” said Cromarty.

Measuring moisture underground to gauge vegetation above

Alongside weather data, fuel levels are a key component of gauging wildfire risks. More dry grass and brush buildup means more chance of fire ignition and spread. But until recently, there has been no simple way to estimate fuel quantity across large areas, said Cromarty, especially in remote and inaccessible wilderness areas.

Now there is a way. Experts can approximate vegetative ground cover through soil moisture estimations. And they can calculate soil moisture across large, even remote areas, using GNSS reflectometry, a satellite remote sensing technique that measures how GNSS signals scatter off the Earth’s surface. It’s particularly adept at evaluating wide areas where it’s impractical to deploy people.

Some of Spire’s satellites already collect these measurements and coverage will expand as we launch more cubesats, promising another tool in the wildfire management toolbox.

Dry season versus wet season

“Our upcoming launches will continue to improve soil moisture readings and weather forecasting,” said Cromarty, “ensuring emergency management teams will gain increased insight and detail with every successive launch.”

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