Atmospheric Rivers as a Component of Multi-hazards and their Influence on Western U.S. Water Management

The Forecast Informed Reservoir Operations (FIRO) initiative, led by the United States Army Corps of Engineers (USACE) in collaboration with multiple agencies and university partners, marks a significant shift in integrating advanced weather and hydrologic forecasting into reservoir management, particularly on the US West Coast. At the heart of FIRO is the utilization of the predictability of atmospheric river (AR) landfall over multi-day timescales. However, challenges remain in fully understanding and predicting the interactions of ARs with critical environmental conditions, such as post-burn fire scars, saturated watersheds, and heavy snowpack, as well as other phenomena that contribute to hazards, including in the context of water management. Given the evolving patterns of rain, snow, and wildfires in the region, these factors underscore the urgency for proactive insights into multi-hazards and their effect on water management.

In addressing these challenges, our project conducts a thorough analysis of literature regarding ARs as drivers of hazards and their contributions to multi-hazard events, noting that their interactions vary geographically and temporally in response to climate change, necessitating spatially distributed climate change adaptation strategies for USACE water management for hazard conditions. This project is complimented by the creation of a comprehensive multi-hazard inventory for California, encompassing various hazards across different timescales. This inventory is supported by diverse data sources, including the NOAA NCEI Storm Event Data, the Rutz AR Catalog, USGS/USDA Monitoring Trends in Burn Severity Fire Data, and USACE's annual state-level flood damage reports. A key aspect of our study is the inclusion of the location of USACE infrastructure, particularly dams and reservoirs, to identify those most vulnerable to multi-hazard events historically.

The outcomes of this project are anticipated to offer critical insights and practical tools for decision-makers within the USACE water management community and beyond. These tools and insights are aimed at equipping them to better navigate the complex and evolving challenges presented by climate change. Through this initiative, we aim to contribute significantly to the development of more resilient and adaptive water management strategies in the face of a dynamic and changing environment.