The 2014 monsoon delivered above-average rain to most of Arizona and New Mexico in the past 30 days, according to the August Southwest Climate Outlook from CLIMAS. Rain has fallen consistently throughout the season in New Mexico, but has been both spatially patchy and temporally sporadic in Arizona, with fewer large storm events. Above-average precipitation is forecast to continue in the long-term, along with below-average temperatures, especially as an El Niño event continues to develop, albeit weaker than previously predicted.
The current drought gripping the western U.S. has resulted in a nearly 63 trillion gallon water deficit—equivalent to the annual ice loss from Greenland—which is causing the land to rise across the western U.S., according to a recent study published in Science. The authors used highly precise GPS stations to record the uplift, which is due to less water weighing down the land surface, and then inverted the measurements to estimate mass loss. On average, the region has risen about 0.15 inches, while mountains in California have risen by more than half an inch.
Climate change will increase the frequency of stream drying events in the Southwest U.S., further threatening already endangered fish species, according to a new paper published in PNAS. By modeling future streamflow of the Verde River Basin in Arizona, the authors found that the frequency of zero-flow days will increase by 27 percent by mid-century. In addition, the frequency of stream drying events, in which portions of the channel dry, leading to fragmented, isolated pools, will increase by 17 percent, most significantly affecting spring spawning when fish travel further.