How We Discovered the Sierra Nevada Snowpack Is at a 500-Year Low

By Measuring the Widths of Centuries-Old Trees and Collecting Deadwood, My Team and I 'Read' the History of California's Climate

A tiny patch of snow sits in the shade of a tree at the site of a California Department of Water Resources snow survey in Phillips, California May 1, 2014. The reading at Phillips is zero, where it typically averages roughly 40 inches of snow on May 1, and the statewide snowpack water content is at 18 percent of average. REUTERS/Max Whittaker (UNITED STATES - Tags: ENVIRONMENT SOCIETY) - RTR3NGCX

In 2005, I moved to the U.S. from Belgium to study the influence of climate on wildfires in the Sierra Nevada over the last five centuries. As part of this work, I travelled for three months all around the mountain range to collect samples of trees and tree stumps. I stayed in remote service barracks and spent my days tromping through meadows and hiking up steep creeks to find trees that were scorched by past fires. On more than one occasion, I found myself wondering whether a nearby roar I …

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