Study Develops Framework for Forecasting Contribution of Snowpack to Flood Risk During Winter Storms

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In the Sierra Nevada, midwinter “rain-on-snow” events occur when rain falls onto existing snowpack and have resulted in some of the region’s biggest and most damaging floods. 

In the Sierra Nevada, midwinter “rain-on-snow” events occur when rain falls onto existing snowpack and have resulted in some of the region’s biggest and most damaging floods. Rain-on-snow events are projected to increase in size and frequency in the coming years, but little guidance exists for water resource managers on how to mitigate flood risk during times of rapidly changing snowpack. Their minute-by-minute decisions during winter storms can have long-lasting impacts to people, property, and water supplies.

A new study by a team from DRI, University of California, Berkeley, the National Weather Service, and University of Nevada, Reno, provides the first framework for a snowpack decision support tool that could help water managers prepare for potential flooding during rain-on-snow events, using hourly data from existing snow monitoring stations.

“During rain-on-snow events, the people managing our water resources always have decisions to make, and it’s really challenging when you’re dealing with people’s lives and property and livelihood,” said DRI Graduate Assistant and lead author Anne Heggli, M.S. “With this work, we’re leveraging existing monitoring networks to maximize the investment that has already been made, and give the data new meaning as we work to solve existing problems that will potentially become larger as we confront climate change.”

Read more at Desert Research Institute

Image: Lead author Anne Heggli of DRI digs through deep snow to reach a monitoring site during a 2019 field project at the UC Berkeley Central Sierra Snow Laboratory in the Tahoe National Forest. (Credit: M. Heggli)