Fifty Years of Landsat: Watchman for Wildfires

Part 5 of a Six-part Series Highlighting the 50th Anniversary of Landsat

By Communications and Publishing July 20, 2022

Earth imagery is fundamental to the USGS fire mission to understand the causes, consequences, and benefits of wildfire. Imagery and data from Landsat satellites also provide information and tools that are widely used for decisions before, during, and after wildfires across the nation. This valuable intel helps prevent and manage larger, catastrophic events.

Worldwide, fire plays a critical role in maintaining the resilience of ecosystems such as forests and grasslands. Yet, unplanned wildfires can be undeniably damaging to local communities and ecosystems. Homes and other structures can be destroyed, and air quality can be impacted for miles. During the long summer months, wildfires occur more often and with greater intensity. Data and imagery from the joint USGS/NASA Landsat satellites play a critical role in understanding the impact, severity, and extent of large fires.

Landsat satellites have been collecting information about wildfires since the 1970s, helping land managers and emergency responders assess the impact of fires on ecosystems and communities. Landsat satellites document the location and extent of burned areas, the severity of the burn mosaic, and the subsequent regrowth long after the smoke clears. All this information helps land managers better care for our landscapes and natural resources amid continued and evolving wildfire dynamics.

Landsat Image of California Caldor Fire - August 14, 2021 — The Caldor Fire in California started on August 14, 2021 and quickly spread in high winds. The fire expanded toward the Lake Tahoe area as residents evacuated. Landsat image was captured on August 21, the 8th day. Landsat 8's near-infrared and shortwave infrared bands reveal active fire, burn scars, and smoke (left). Landsat's thermal and infrared bands also expose the Caldor fire's advancing edge at night time. This image is from August 29, 201, 15 days after ignition (right).

Landsat Image of California Caldor Fire - August 29, 2021 — The Caldor Fire in California started on August 14, 2021 and quickly spread in high winds. The fire expanded toward the Lake Tahoe area as residents evacuated. Landsat image was captured on August 21, the 8th day. Landsat 8's near-infrared and shortwave infrared bands reveal active fire, burn scars, and smoke (left). Landsat's thermal and infrared bands also expose the Caldor fire's advancing edge at night time. This image is from August 29, 201, 15 days after ignition (right).

Fire-Adapted Ecosystems

Wildland fire – a term that includes both wildfires and prescribed fires – can be used by land managers to restore historical forests, preserve old growth, increase plant diversity, detect fire-adapted invasive species, reduce hazardous fuels, and lessen future wildfire risk for the benefit of agriculture, ranching, forestry, and wildlife management.

Managing fire on landscapes requires understanding the role that fire has historically played, and archived Landsat data is invaluable for glimpsing into past fire regimes. For example, the USGS is a partner in the interagency Monitoring Trends in Burn Severity program, which maps the severity and extent of large fires across all lands of the United States using remote sensing data from 1984 to the present. Landsat remote sensing data is also used in the joint Department of Interior (DOI) - U.S. Forest Service (USFS) LANDFIRE program, which produces Landscape Fire and Resource Management Planning Tools. LANDFIRE products such as the Fire Regime Groups support cross-boundary wildland fire modeling, planning, management, and operations.

Detecting Fires Early

Over the past two decades, we have observed a rapid escalation of extreme wildfire behavior. These unplanned wildfires are expensive to manage. Even though only a small percentage each year become large, damaging infernos, there have been significant increases in the risks each year to responders and citizens. Those that do escape containment cause home and property losses, local economic costs, and threats to extended communities and landscapes. Last year, according to the National Fire Activity Synopsis, more than 58,985 wildfires were reported, consuming nearly 7.13 million acres and destroying more than 5,970 structures. This figure included 3,577 residences, 2,225 minor structures, and 237 commercial/mixed residential structures.

It’s not just homes and businesses burned in wildfires. These fires cause many other social, economic, and environmental effects. According to the National Interagency Fire Center, it costs an average of \$5 billion a year to respond to wildfires. Economic effects of wildfires total in excess of \$71 billion each year, according to a 2017 National Institute of Technology review.

Because instruments on the Landsat satellites can detect thermal anomalies (temperature differences) over broad areas, they can also help detect wildfires burning in remote regions. The locations of new fires can be sent directly to land managers worldwide within hours of the satellite overpass. Processing of Department of Defense and Intelligence Community sensor data for wildfire applications, coordinated by the USGS National Civil Applications Center, enables enhanced fire detection and perimeter mapping in some regions.

Landsat 8 Image of Washburn Fire, Yosemite National Park - July 7, 2022 — The Washburn Fire started July 7, 2022 in the southern part of Yosemite National Park. Landsat 8 and 9 both captured imagery of it a day later. The Landsat 9 image uses shortwave infrared and near-infrared bands to show the active burning. The Landsat 8 thermal image was acquired at night to pinpoint the location (bright white) of heat from the fire as it began.

Landsat 9 Image of Washburn Fire, Yosemite National Park - July 7, 2022 — The Washburn Fire started July 7, 2022 in the southern part of Yosemite National Park. Landsat 8 and 9 both captured imagery of it a day later. The Landsat 9 image uses shortwave infrared and near-infrared bands to show the active burning. The Landsat 8 thermal image was acquired at night to pinpoint the location (bright white) of heat from the fire as it began.

Preparation, Response and Recovery

Satellite imagery can be used before, during, and after wildfires for disaster preparation, mitigation, response, and recovery. In fact, there is demonstrated cost effectiveness of such information and Landsat data is a critical for rapidly assessing burned areas, through programs such as the DOI Burned Area Rehabilitation (BAR) and the Forest Service’s Burn Area Emergency Response (BAER). USGS also does burn severity mapping on non-federal lands to support post-fire response. Burn severity mapping programs identify imminent post-wildfire threats to human life and safety, property, and critical natural or cultural resources. BAER, for example, has been estimated to yield cost savings of up to $35 million over a five-year period. By using Landsat data to map vegetation, water and soil changes after a fire, response staff can identify the patchwork of burned areas left in the wake of the flames. By assessing the severity of the burn mosaic, experts can identify recommended treatments to mitigate further damage from the increased runoff and erosion that occurs on burned landscapes.

Landsat can provide accurate and complete data on fire locations and burned areas that is nearly impossible to capture from ground operations, especially in remote areas with rugged terrain - information that is needed to quantify trends and patterns of fire occurrence, characterize drivers of fire occurrence, projections of future fire pattern behavior, and help with assessments of fire impacts on both natural and social systems.

Landsat Before Dixie Fire, CA - July 11, 2021 — In August 2021, the Dixie Fire became the largest single fire in California's recorded history. State fire officials don't list it at the top, however. The record is held by the massive August Complex Fire of 2020, which burned over one million acres. The term "complex" is used when multiple fires in the same area ignite separately. Designating the fires as a complex allows them to be managed under a unified command. The Dixie Fire ignited on July 13, 2021 near Cresta Dam in the Feather River Canyon. Nine days later the Fly Fire started 3.5 miles north of Quincy eventually merging into the much larger Dixie Fire. Hot weather and strong winds spread the blaze across national forests and into Lassen Volcanic National Park. These near-infrared and shortwave infrared images cut through smoke to highlight burned areas.

Landsat After Dixie Fire, CA - August 12, 2021 — In August 2021, the Dixie Fire became the largest single fire in California's recorded history. State fire officials don't list it at the top, however. The record is held by the massive August Complex Fire of 2020, which burned over one million acres. The term "complex" is used when multiple fires in the same area ignite separately. Designating the fires as a complex allows them to be managed under a unified command. The Dixie Fire ignited on July 13, 2021 near Cresta Dam in the Feather River Canyon. Nine days later the Fly Fire started 3.5 miles north of Quincy eventually merging into the much larger Dixie Fire. Hot weather and strong winds spread the blaze across national forests and into Lassen Volcanic National Park. These near-infrared and shortwave infrared images cut through smoke to highlight burned areas.

For more information on the USGS Landsat program, go to: https://www.usgs.gov/landsat-missions

For more information about the USGS support of and participation in wildfire science, go to this interactive Story Map: https://wim.usgs.gov/geonarrative/firescience/

In case you missed it

Parts 1, 2, 3, and 4 of the Six-part Series Highlighting the 50th Anniversary of Landsat: