Monsoon has limited impact on Colorado mountain streamflow

Summer rains won't compensate for diminished snowpack

Feb 9, 2021 - by Staff

With climate change leading to diminished snowpack in the Rocky Mountains, a new study warns that summertime rains are unlikely to significantly bolster stream levels.

The study, which focused on a snow-dominated headwater basin of the Colorado River, found that rain from the North American Monsoon generally has limited impacts on streamflow at lower elevations. Mountain forests such as dense aspen and conifer forests consume much of the water before it makes its way into streams. In drier years with reduced snowpack, the monsoon provides even less benefit for streamflow because more of the rain is absorbed into the soil and quickly evaporates back to the atmosphere.

“The monsoon can be important for summertime moisture and ecosystems in the Southwest, but unfortunately it’s not going to compensate for diminishing snowpack with regard to streamflows,” said Dave Gochis, a scientist at the National Center for Atmospheric Research (NCAR) who co-authored the study.

The study was led by the Desert Research Institute and published in Geophysical Research Letters. For more about the research, see the Desert Research Institute news release

See all News