Defining Snow Drought and Why It Matters

American Geophysical Union (AGU) | February 28th, 2017

On 12 February, water resource managers at the Oroville Dam issued an evacuation warning that forced some 180,000 Californians to relocate to higher ground. The story of

On 12 February, water resource managers at the Oroville Dam issued an evacuation warning that forced some 180,000 Californians to relocate to higher ground. The story of how conditions got to this point involves several factors, but two clearly stand out: the need to prevent water shortages during a record drought, followed by one of the wettest October–February periods in California history.

Delta Salinity Management Workshops 2022 Information Sheet

Delta Stewardship Council (Delta Council) | March 7th, 2022

Designing Drought Indicators

American Meteorological Society (AMS) | November 25th, 2019

Drought indicators hold great potential to assist water management. However, drought information products are traditionally designed by scientists with little input from

Drought indicators hold great potential to assist water management. However, drought information products are traditionally designed by scientists with little input from the end users. This has resulted in an inundation of products ill suited to stakeholder needs and requirements, limiting the potential for improving management through the use of these products. In a different field—the field of product design—product designers and strategists have matured methodologies for optimizing the creation of material products, such as shoes and cars, for example, for customers. A multitude of design-centric strategies are employed to determine customer needs and requirements (e.g., lighter shoe, more cushioning, breathable, reflectivity, arch support, width options, color options). These approaches can be extended from material to information or data products. Here, we describe how the methodological approaches within the field of product design can be interdisciplinarily employed to data products for drought indicators, with water managers as end users (i.e., the “customers”). New results for drought data products may be transformative in how drought indices are constructed, communicated, and delivered, with potentially significant improvements for water management.

Drought and Equity in California

Pacific Institute | January 9th, 2017

Drought and Equity in California is the first statewide analysis of the impacts of the drought on California’s most vulnerable communities. This report provides informa

Drought and Equity in California is the first statewide analysis of the impacts of the drought on California’s most vulnerable communities. This report provides information community groups can use to advocate for their own interests, as well as to inform policymakers and other decision-makers interested in crafting more effective drought response strategies, particularly to address the needs of the state’s most vulnerable communities. The report finds that during the state’s ongoing drought, water shortages and price hikes affected access to safe, affordable water for Californians, with substantial impacts on low-income families and communities burdened with environmental pollution. The report also examines the effects of a rapidly declining salmon population on commercial and tribal fishermen and finds that the decline and variability of salmon populations during droughts has impacted those dependent on the fish for income, food, and cultural traditions.

Drought and Equity in the San Francisco Bay Area

Pacific Institute | June 29th, 2016

California’s ongoing drought has wide-reaching impacts, from how we grow crops to the price of electricity. Often overlooked is its impact on disadvantaged communities.

California’s ongoing drought has wide-reaching impacts, from how we grow crops to the price of electricity. Often overlooked is its impact on disadvantaged communities. The Pacific Institute and The Environmental Justice Coalition for Water (EJCW) conducted community-based participatory research with eight Bay Area community-based groups to explore and document the drought’s impacts on low-income people in the San Francisco Bay Area. Through a series of collaborative meetings, surveys, and in-depth analyses of data, the group produced a groundbreaking report that sheds light on specific drought-related hardships faced by low-income residents and offers recommendations for mitigating those impacts. “This report is the first examination of the drought’s impacts on low-income communities in the Bay Area,” says Colin Bailey, Executive Director of EJCW. “Contrary to the conventional wisdom, the report shows the same hardships that befall California’s more rural communities are present in urban areas as well. The report calls on decision makers to account for and address these inequities in our drought responses.” The project team examined available data on drought impacts for the Bay Area, such as the number of households without water. The group identified affordability and water infrastructure conditions as key concerns for low-income communities, along with inequitable water use, whereby wealthier households typically use more water than lower income households. These are persistent concerns in many communities but have been exacerbated by the drought.

Drought and Groundwater Sustainability in California’s Farming Regions

Public Policy Institute of California (PPIC) | June 25th, 2024

Drought and ozone air quality in California: Identifying susceptible regions in the preparedness of future drought

Environmental Research (Elsevier) | October 19th, 2022

California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our st

California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our study quantified site-specific associations between drought (defined by the Standardized Precipitation-Evapotranspiration Index; SPEI) and daily maximum 8-h ozone (O3) concentrations for California, USA, and then pooled these associations for the years 2009–2015. Overall, ambient O3 concentration was higher during droughts by 1.18 ppb (95% confidence interval (CI) = 1.00–1.36). The sensitivity of O3 to drought was greater during the warm season than during the cool season (1.73 ppb versus 0.79 ppb higher O3 during droughts) with substantial regional variation. In a pooled analysis with meteorological parameters as potential effect modifiers, the spatial heterogeneity of drought-O3 associations was explained strongly by average relative humidity for each season (71.9% (warm season) and 73.4% (cool season) of the drought-O3 associations explained), followed by the drought-related changes in relative humidity (47.6% (warm season)) and temperature (53.6% (cool season)). The pooled regression further identified regions susceptible for drought-related O3 increases as those with relatively low average relative humidity (10–25th percentiles or 44.3–47.3%) and larger drought-related decrease in relative humidity and increase in temperature. As the drought events are projected to occur with increased frequency and intensity in the era of climate change, the excess health burdens from O3 exposures attributed to the projected drought events need to be taken into account when allocating air quality and health resources. The impacts of O3 on health during droughts would confound the health burdens from the drought itself.

Drought and the California Delta—A Matter of Extremes

University of California, Davis (UC Davis) | July 14th, 2014

California is in an extreme drought as a result of low precipitation in water year 2012, record low precipitation in 2013, and the remarkably dry first few months of 2014

California is in an extreme drought as a result of low precipitation in water year 2012, record low precipitation in 2013, and the remarkably dry first few months of 2014. We typically receive our largest precipitation totals in Decembers and Januaries (which provide about 36% of the precipitation in the Delta’s catchment), and when those months are as dry as they were this year, subsequent months have to be unseasonably wet to avoid drought. Most of the current winter, especially December 2013–January 2014, was dry because a persistent ridge of high (atmospheric) pressures set up offshore, diverting storms away from California and into Alaska. That same diversion gave the Delta’s catchment its warmest winter in 120 years, as well as bringing all that cold weather to the eastern US. While the February 2014 storms provided minor relief and momentarily slowed the spiral into deeper drought, the drought continues apace. Nonetheless, as harsh as it is, the current drought is not unprecedented in the Delta’s history, and even less so in its prehistory. In this essay, we consider the ways that droughts in California arise from a few missing storms and from long-term variations and changes in climate, in order to identify drought-science needs for Delta management. 

Drought and Water Year 2016: Hot and Dry Conditions Continue

California Department of Water Resources (DWR) | September 15th, 2016

Drought is a recurring feature of California’s climate. Paleoclimate information, such as streamflow or precipitation reconstructions developed from tree-ring d

Drought is a recurring feature of California’s climate. Paleoclimate information, such as streamflow or precipitation reconstructions developed from tree-ring data, can provide a perspective on long-term climate variability. Reconstructed hydrologic records show that California has experienced droughts of much longer duration than those in our century- plus recorded historical period. There is, however, one drought within the historical period on a par with driest events in the paleo record, if the comparison is made using driest 10-year streamflow periods. The prolonged off-and-on dry conditions of the 1920s-30s were severe in terms of their hydrology, but they occurred at a time when the state’s population was in the ballpark of 6 million and irrigated acreage was less than half of present levels.

Drought Attribution Studies and Water Resources Management

American Meteorological Society (AMS) | February 16th, 2023