Tim Brown

Smoke and Weather: Using data to make better decisions

Lake Tahoe’s environmental agencies often prepare for fire season by burning potential fuel like shrubs and grass. But before the U.S. Forest Service (USFS) can pack their gear and head deep into the basin’s forests, they have to check the weather first.

Tim Brown, director of the Western Regional Climate Center (WRCC) and the Desert Research Institute’s Climate, Ecosystem and Fire Applications program (CEFA), provides Lake Tahoe agencies with weather and climate information to lessen the impact that prescribed fires have on the air. Smoke particles can cause respiratory problems among Tahoe’s residents or settle into the lake, dampening its clarity.

“In places like Tahoe, which is this giant bowl, it’s easy for colder air to settle,” Brown said. “If you have a fire going, what you don’t want is for that smoke to settle with the colder air. Ideally, you want the smoke to rise and let upper level winds disperse it so it doesn’t impact anybody.”

For smoke to not settle into the basin, the mixing height, a lower layer of the atmosphere with rising air, needs to be high enough to where winds can scatter the smoke over a larger area. Brown generated maps from an atmospheric model to help understand the mixing heights’ daily patterns. Environmental agencies can refer to these maps to strategically plan for burns.

“As a fire manager, what you want to do for planned burns is to reduce hazardous fuels and create a healthy forest and landscape environment,” Brown said. “But in trying to meet these objectives, you also don’t want to impact people by putting the smoke in their houses, schools or hospitals.”

Brown and his team also work with the USFS to maintain online tools, which combine weather and smoke models. The USFS AirFire group developed a tool called Bluesky Playground that local agencies can use to plan burns. The agencies can enter information about their planned burn into the tool, including the fuel contents and how long the burn will last. The tool then estimates how much smoke to expect and, using the weather models that Brown developed, estimates how high and how far the smoke might go.

“You don’t want to impact individuals or put out so much smoke that you’re exceeding a regulatory threshold,” Brown said.

Brown’s modeling domain extends beyond the Lake Tahoe Basin and includes California and Nevada. As the director of the WRCC and the CEFA, he also monitors a nationwide network of climate information, remote weather stations and lightning strike centers. He provides climate, fire danger and smoke management information to agencies such as the USFS.

Brown believes in approaching environmental issues like fire and climate from different perspectives and with different data to better aid management agencies in solving complex issues. Decisions like conducting a prescribed burn on the wrong day could have repercussions in the environment and with local residents.

“In my view, you can’t really talk about the physical aspects of fire without the societal aspects of fire,” Brown said. “Some decisions could really have an impact on society, on health, safety and quality of life. There could also be a large economic component to these decisions.”

Brown’s interests in examining different perspectives of a problem using data may be a product of his background. He started college in meteorology, but eventually switched to astronomy, inspired by boyhood evenings scanning the skies with his grandfather on the family farm in Illinois. Now with a master’s and doctoral degree in climatology, he’s working to make fire climate and weather information useful to decision makers.

“A challenge for me was to learn about the fire management system, so I could combine the physical and societal aspects of fire and perform research with a more holistic viewpoint,” he said.

Though he has been working on fire and climate issues since the 1990s, Brown knows there is still much more to learn. “Fire-climate didn’t really become in vogue until this past decade. Now the conflating of climate change, fire and people are generating whole new areas of research and societal challenges.”