Collaborative Research: P2C2-Inferring Spatio-Temporal Variations in the Risk of Extreme Precipitation in the Western United States from Tree Ring Chronologies

Lead PI: A. Park Williams , Dr. Upmanu Lall , Dr. Edward R. Cook , , Michelle Ho

Unit Affiliation: Biology and Paleo Environment, Lamont-Doherty Earth Observatory (LDEO)

September 2017 - August 2020
North America ; United States ; Western United States
Project Type: Research

DESCRIPTION: This project aims to understand extreme cold-season precipitation dynamics along the west coast of the United States through an analysis of the moisture anomalies recorded by tree-ring chronologies across the coast and interior of the western U.S. Winters with high total precipitation amounts in the coastal regions are marked by a small number of extreme storms that exhibit distinct spatial patterns of precipitation across the coast and further inland. Building from this observation, this research will seek to develop a novel application of dendroclimatic evidence to explore the following questions: a) how is extreme precipitation variability expressed in a network of tree-ring chronologies; b) can this information provide insight on the space-time variability of storm tracks that cause these extreme events; and c) how can the joint variability of extreme precipitation and storm tracks be modeled to develop consistent, multi-centennial reconstructions of both.

The broader impacts include the potential to better understand extreme precipitation events which exert significant social costs through both loss of life and substantial damage to property. Society manages this burden using risk mitigation strategies (e.g., infrastructure, insurance) designed for historic extreme precipitation variability that is estimated from relatively short instrumental records and may be changing under anthropogenic climate change. This project will help determine how the frequency, persistence, recurrence and geographic pattern of these impacts have varied in the past under natural climate variability. This will provide important insights into the causes of these shifts and the potential for predictability in the future. This project also provides support for graduate and post-doctoral researchers.

Outreach efforts will focus on high-level discussions with the L.A. County Flood Control District, U.S. Army Corps of Engineers, and related agencies that manage extreme event risk in the region. This direct engagement will enhance the application of the research products, as well as provide guidance for their design. Innovative visualizations of research output will be made available through the Columbia Water Center for public use.


National Science Foundation (NSF)




Columbia Water Center (CWC)



Steinschneider, Scott and Ho, Michelle and Williams, A. Park and Cook, Edward R. and Lall, Upmanu. "A 500-Year Tree Ring-Based Reconstruction of Extreme Cold-Season Precipitation and Number of Atmospheric River Landfalls Across the Southwestern United States," Geophysical Research Letters, v.45, 2018. doi:10.1029/2018GL078089


climate change precipitation extreme storms risk mitigation tree rings tree ring chronologies dendroclimate


Modeling and Adapting to Future Climate