Social and Behavioral Sciences Commons^™

Increasing Heat-Stress Inequality In A Warming Climate, Mohammad Reza Alizadeh, John T. Abatzoglou, Jan F. Adamowski, Jeffrey P. Prestemon, Bhaskar Chittoori, Ata Akbari Asanjan, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Adaptation is key to minimizing heatwaves' societal burden; however, our understanding of adaptation capacity across the socioeconomic spectrum is incomplete. We demonstrate that observed heatwave trends in the past four decades were most pronounced in the lowest-quartile income region of the world resulting in >40% higher exposure from 2010 to 2019 compared to the highest-quartile income region. Lower-income regions have reduced adaptative capacity to warming, which compounds the impacts of higher heatwave exposure. We also show that individual contiguous heatwaves engulfed up to 2.5-fold larger areas in the recent decade (2010–2019) as compared to the 1980s. Widespread heatwaves can overwhelm …

Warming Enabled Upslope Advance In Western Us Forest Fires, Mohammad Reza Alizadeh, John T. Abatzoglou, Charles H. Luce, Jan F. Adamowski, Arvin Farid, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Increases in burned area and large fire occurrence are widely documented over the western United States over the past half century. Here, we focus on the elevational distribution of forest fires in mountainous ecoregions of the western United States and show the largest increase rates in burned area above 2,500 m during 1984 to 2017. Furthermore, we show that high-elevation fires advanced upslope with a median cumulative change of 252 m (−107 to 656 m; 95% CI) in 34 y across studied ecoregions. We also document a strong interannual relationship between high-elevation fires and warm season vapor pressure deficit (VPD). …

Western Fires Are Burning Higher In The Mountains At Unprecedented Rates: It’S A Clear Sign Of Climate Change, Mojtaba Sadegh, John Abatzoglou, Mohammad Reza Alizadeh

Civil Engineering Faculty Publications and Presentations

The Western U.S. appears headed for another dangerous fire season, and a new study shows that even high mountain areas once considered too wet to burn are at increasing risk as the climate warms.

Nearly two-thirds of the U.S. West is in severe to exceptional drought right now, including large parts of the Rocky Mountains, Cascades and Sierra Nevada. The situation is so severe that the Colorado River basin is on the verge of its first official water shortage declaration, and forecasts suggest another hot, dry summer is on the way.

Warm and dry conditions like these are a recipe …

Compound Extremes Drive The Western Oregon Wildfires Of September 2020, John T. Abatzoglou, David E. Rupp, Larry W. O'Neill, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Several very large high‐impact fires burned nearly 4,000 km² of mesic forests in western Oregon during September 7–9, 2020. While infrequent, very large high‐severity fires have occurred historically in western Oregon, the extreme nature of this event warrants analyses of climate and meteorological drivers. A strong blocking pattern led to an intrusion of dry air and strong downslope east winds in the Oregon Cascades following a warm‐dry 60‐day period that promoted widespread fuel flammability. Viewed independently, both the downslope east winds and fuel dryness were extreme, but not unprecedented. However, the concurrence of these drivers resulted in compound extremes …

Wildfires Force Thousands To Evacuate Near Los Angeles: Here’S How The 2020 Western Fire Season Got So Extreme, Mojtaba Sadegh, Ata Akbari Asanjan, Mohammad Reza Alizadeh

Civil Engineering Faculty Publications and Presentations

Two wildfires erupted on the outskirts of cities near Los Angeles, forcing more than 100,000 people to evacuate their homes Monday as powerful Santa Ana winds swept the flames through dry grasses and brush. With strong winds and extremely low humidity, large parts of California were under red flag warnings.

High fire risk days have been common this year as the 2020 wildfire season shatters records across the West.

More than 4 million acres have burned in California – 4% of the state’s land area and more than double the previous annual record. Five of the state’s six largest historical …

Increasing Concurrence Of Wildfire Drivers Tripled Megafire Critical Danger Days In Southern California Between 1982 And 2018, Mohammad Sadegh Khorshidi, Philip E. Dennison, Mohammad Reza Nikoo, Amir Aghakouchak, Charles H. Luce, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

Wildfire danger is often ascribed to increased temperature, decreased humidity, drier fuels, or higher wind speed. However, the concurrence of drivers—defined as climate, meteorological and biophysical factors that enable fire growth—is rarely tested for commonly used fire danger indices or climate change studies. Treating causal factors as independent additive influences can lead to inaccurate inferences about shifting hazards if the factors interact as a series of switches that collectively modulate fire growth. As evidence, we show that in Southern California very large fires and 'megafires' are more strongly associated with multiple drivers exceeding moderate thresholds concurrently, rather than direct relationships …

Changes In The Exposure Of California’S Levee-Protected Critical Infrastructure To Flooding Hazard In A Warming Climate, Iman Mallakpour, Mojtaba Sadegh, Amir Aghakouchak

Civil Engineering Faculty Publications and Presentations

Levee systems are an important part of California's water infrastructure, engineered to provide resilience against flooding and reduce flood losses. The growth in California is partly associated with costly infrastructure developments that led to population expansion in the levee protected areas. Therefore, potential changes in the flood hazard could have significant socioeconomic consequences over levee protected areas, especially in the face of a changing climate. In this study, we examine the possible impacts of a warming climate on flood hazard over levee protected land in California. We use gridded maximum daily runoff from global circulation models (GCMs) that represent a …

Probabilistic Hazard Assessment Of Contaminated Sediment In Rivers, Shahab Aldin Shojaeezadeh, Mohammad Reza Nikoo, Ali Mirchi, Iman Mallakpour, Amir Aghakouchak, Mojtaba Sadegh

Civil Engineering Faculty Publications and Presentations

We propose a probabilistic framework rooted in multivariate and copula theory to assess heavy metal hazard associated with contaminated sediment in freshwater rivers that provide crucial ecosystem services such as municipal water source, eco-tourism, and agricultural irrigation. Exploiting the dependence structure between suspended sediment concentration (SSC) and different heavy metals, we estimate the hazard probability associated with each heavy metal at different SSC levels. We derive these relationships for warm (spring-summer) and cold (fall-winter) seasons, as well as stormflow condition, to unpack their nonlinear associations under different environmental conditions. To demonstrate its efficacy, we apply our proposed generic framework to …

Wildfire Smoke: Trends, Challenges, Unknowns, And Human Response, Mariah Dawn Fowler

Boise State University Theses and Dissertations

Wildfire smoke is a growing threat to human livelihood in the Western United States. The economic and the health burden of smoke is accelerating in response to a growing fire season and escalating fire activity. This study first evaluates the trends in air quality over Boise, Idaho and the entire Northwest (and Montana) to assess the impacts of wildfire smoke in the region. The Mann-Kendall trend analysis shows that there is a statistically significant trend in the average and maximum air quality index (AQI) during the fire season (July-August-September) in the Boise area. The AQI shows a decreasing trend, although …