The Evolution and Impacts of the 2018 Four Corners Drought in the Southwest United States

What may likely be considered the worst drought on record for the Four Corners region, encompassing parts of Colorado, Utah, Arizona, and New Mexico, began in the fall of 2017. The very beginnings can be linked to a poor performing North American Monsoon in the late summer of 2017, which transitioned to an anomalously warm snow drought as the winter progressed. Much of the region experienced its warmest winter on record. Winter precipitation around many areas totaled around 50% of average or less, and by the beginning of March 2018, 31 SNOTEL sites in the Upper Colorado River Basin observed snow water equivalent ranked in the driest 0-5^th percentiles.

In the spring, the results of extreme snowpack deficits manifested as early and low peak streamflows. During a time when rivers substantially rise and water supplies are replenished in reservoirs, flows peaked well below average and some reservoirs saw minimal increases in levels. Summer came with continued above average temperatures, increased water demand, and high evaporative stress on crops, forests, and vegetation. Major wildfires were a significant issue. While some areas saw relief with the onset of the 2018 North American Monsoon, it didn’t extend as far north as hoped. As the 2018 water year (October 1, 2017 – September 30, 2018) wrapped up, the hydrologic effects from this drought were evident on the record low-flowing rivers and the stressed water resources.

Impacts from this drought have been broad, including the agricultural sector, water, tourism and recreation, forests, and wildlife. During a drought tour in southwest Colorado in July 2018, a rancher indicated how long it takes to repopulate a culled herd, farmers expressed frustration with not having access to water, a professional with a local ski resort talked about a decrease in visitors, and a local railroad company detailed its struggles as it shut down during peak season because of a large wildfire. As recent research has suggested this region may actually be experiencing aridification, it’s especially important now to connect with the community and understand the impacts so that we can help those most vulnerable to drought.