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A crystal ball sure seems like it would come in handy during fire seasons, showing exactly where and when a fire might roar through and how large it could be.

Science can’t give us all the details, but it can give us models to indicate where a fire might really take off or where it might be easily contained in a given year.

color maps of Modeling Dynamic Fuels with an Index System (MoD-FIS) map data
These MoD-FIS maps comparing 2019 and 2021 herbaceous vegetation in Nevada reveal areas that have become more barren (black) and sparse (pink). (Courtesy: Charley Martin)

In their work with the Landscape Fire and Resource Management Planning Tools (LANDFIRE) Program, Charley Martin and Tobin Smail work with that type of geospatial mapping model, one based on a vegetation index built with Landsat satellite data. Martin and Smail both draw from their deep wildland firefighting backgrounds and fuels work to supply fire managers in the western U.S. with current seasonal herbaceous, or grass, cover and its variance from the average.

Everyone knows that 2021 has been hot and dry. The model Martin and Smail use, Modeling Dynamic Fuels with an Index System (MoD-FIS), supplies three products a year to give land managers an idea of how lack of moisture has changed herbaceous vegetation and, therefore, potential fire fuel. A separate MoD-FIS effort provides drought information for the southeastern U.S.

In the western U.S., the model shows more barren and sparse areas of land this year—the most since the MoD-FIS releases began a handful of years ago, Martin said. Less vegetation, such as grasses, in lowland areas typically would indicate less fuel than normal to feed a fire and make it easier to contain.

“The arrangement of how that grass is spread out over a pixel—30-by-30-meter pixel—is really important to how the fire is going to spread,” Martin said. “If there’s big barren spots in there that the fire can’t cross, because there’s no grass there, then the fire’s not going to go anywhere. The way the grass is arranged, if it’s continuous, then the fire has a chance of becoming a large fire. But if it’s spotty … the fire wouldn’t be able to travel.”

Less grass doesn’t mean less fire risk, however. “There’s still plenty of country in the higher elevation in the Southwest to really cause some problems,” Smail said.

One user of MoD-FIS data is a meteorologist and fire behavior analyst who prepares a regional outlook for wildfires in the Southwest, Martin said. His outlook indeed predicts more fires in the higher regions’ forested areas.

Help Planning for Fire Seasons

Fire and fuels specialists can look at products like MoD-FIS and make plans for the coming fire season—where to concentrate resources, for example, or where preventive treatments could be applied. The three MoD-FIS products released each year are a spring vegetation outlook for the Southwest and Northern Great Basin, a summer outlook for those regions and much of the Northwest, and a fall outlook for the Southwest—after a monsoonal season may green up perennial grasses and lead to a second fire season.

Martin and Smail are just the people to understand the needs of fire and fuels specialists, who may help manage State or Federal lands. Martin learned a lot about fire behavior during a couple decades spent guiding western hotshot firefighting crews, mainly for the U.S. Department of Agriculture (USDA) Forest Service, and later worked as a fire ecologist and fire behavior analyst. Smail, too, served as a firefighting hotshot and moved into fire management for various agencies. Production and mapping teams for LANDFIRE are based at U.S. Geological Survey’s Earth Resources Observation and Science (EROS) Center and in remote locations outside of EROS. Funding and program support for LANDFIRE comes from the Department of the Interior’s Office of Wildland Fire and the USDA Forest Service Fire and Aviation Management.

Modeling various fires shows that MoD-FIS—with its attention to barren and sparse land—closely aligns with actual fire perimeters, Martin and Smail said.

“By modeling those fires, it gives us a chance to look at how well we’re predicting things, then make adjustments to those fuel models to increase or decrease our various outputs, just to make it more accurate,” Smail said.


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