This page links to frequently-updated web resources that provide information about current, recent, and forecasted weather and climate, snowpack, streamflow, reservoir levels, and water supply, for the Colorado River Basin. A more comprehensive list of web resources can be found on the Data and tools page.
Interactive maps and tools
These web resources provide multiple ways to view the data, e.g., by selecting a variable, a site or geographic region, or other attributes. In the listings below, links in the bullet items go directly to specific views of the listed variable (e.g., snowpack).
Variability and long-term trends in Colorado River Basin (Powell + Mead) reservoir storage (1935-2025), and in Upper Basin natural streamflow, precipitation, and temperature (1906-2025). This plot first appeared as Figure 2 in Udall and Overpeck (2017), "The twenty-first century Colorado River hot drought and implications for the future." Brad Udall has updated it annually.
The "4-panel plot" showing trends in Colorado River Basin reservoir storage, natural streamflow, precipitation, and temperature, through Water Year 2025. (Figure: Brad Udall; Data: Reclamation - reservoir storage and streamflow; NOAA NCEI - precipitation and temperature)
