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Colorado River Basin drought and the 2023 water year

February 5, 2024

Over the last two decades, the Colorado River Basin has been in an extended drought. This has resulted in substantial changes to the basin, including increased wildfire activity, vegetation shifts, and the depletion of streamflows and water levels in major reservoirs along the Colorado River, notably Lake Powell and Lake Mead. 

In the winter of 2022-23, a series of storms traversed the western U.S. bringing multiple rounds of snow and rain, contributing to a Rocky Mountain snowpack that grew to near-record levels at some locations – making it feel like the drought was over. 

But how wet was it really, when compared to historical averages? 

In this interactive geonarrative, we compare precipitation and streamflow amounts observed during the 2023 water year with historical conditions over the last 30 years, which includes the current 20-year drought (2001-2022) in addition to the 10 years before the onset of the current drought (1991-2001). We show that while the 2023 water year was a wet year with above-average precipitation at many locations, it was not uniformly good or record-setting. 


A map of 4 streamgages along the Colorado stretch of the Colorado River.  Hydrographs for each streamgage are also shown.
March-August daily average streamflow for the last 30 years (1991-2022) (dark gray lines) compared to 2023, showing the periods where 2023 streamflow was above (blue) and below (orange) the historical average. Individual years of the relevant historical streamflow period are shown in light gray. Credit: Kaysa Vaarre-Lamoureux, USGS