Public Understanding of the Atmospheric River Scale

Zoe N. Caryl, Joseph E. Trujillo-Falcón , Anna Wilson, Abby Bitterman

Atmospheric rivers (ARs) are long, narrow bands of moisture in the atmosphere that transport large amounts of water vapor, producing hazards ranging from heavy rain to high winds once they reach land. In 2019, researchers at the Center for Western Weather and Water Extremes, with partners including the National Weather Service and the California Department of Water Resources, developed the AR Scale, which ranges from one to five and categorizes the intensity and potential impacts of ARs to improve communication and public understanding of these events. This study presents the first nationwide, bilingual (English/Spanish) quantitative assessment of the AR Scale in the United States. Using a cross-sectional survey, we examine three key areas: (1) perceived benefits and risks of AR events at different levels, (2) thresholds for taking protective actions during an event based on the AR Scale, and (3) category comprehension of hazard potential. Results provide insight into current levels of public understanding and may help improve the design of forecast products and communication tools used during ARs, supporting better decision-making and response during these high-impact weather events.