Initial forecast: Lakes Mead and Powell headed for record low in 2018

With an underwhelming snowpack right now, the U.S. Bureau of Reclamation’s initial 2018 forecast (pdf here) projects combined storage in Lake Mead and Lake Powell, the two primary reservoirs on the Colorado River, will drop to 21.7 million acre feet by the end of 2018. That would be the lowest Mead/Powell combined year end storage since Powell was first filled in the 1960s.

WARNING: Just this afternoon, I was discussing reservoir storage data with some folks working on Colorado River policy analysis and I strongly discouraged using the 2018 forecast yet. It’s early. It could snow a lot. It also could not snow a lot. The error bars on a forecast made in January are huge, it will almost certainly change in one direction or the other. But for what it’s worth, here’s my updated combined storage graph with the 2018 forecast added.

Storage in Lake Mead, Powell

There’s still enough water in storage to prevent a 2019 Lower Basin shortage declaration. But the risk for 2020 is rising.


  1. Lower Colorado Basin states’ – Arizona , California and Nevada – water officials are hiding the fact that Upper Basin states are only using about 4.4 million acre feet of their allocation of 7.5 million acre feet allowed by the Colorado Compact. The officials are grossly unprepared to deal with a gross water shortage when the Upper Basin states start using their full allocation.

    Sh….Sh.. be quite you might awake the sleeping officials.

Comments are closed.