Arizona is currently in our 26th year of a long-term drought. Drought in the West is a long-term concept where a single dry year does not constitute a drought. Since Arizona has an arid and semi-arid climate, extreme variability in precipitation is normal, and drought is characterized by a string of drier than normal years, often interrupted by a few wetter than normal years. Currently most watersheds in the state have experienced only 9 or 10 normal or wetter than normal years during the past 26 years. The deep canyon topography of the Western U.S. is ideal for creating large reservoirs, such as Lakes Mead and Powell on the Colorado River, and Roosevelt Lake on the Salt River in Arizona. The reservoirs provide an assured water supply in dry years, provided the drought does not last too long. Currently the reservoirs in the Southwest are about half full and are supplying an ever increasing population. For more information about the current status of Arizona reservoirs, see the Salt River Project (SRP) Daily Water Report. For more information about the history of the Salt-Verde Reservoir system, visit SRPs historical website. For current water levels on Lakes Mead and Powell, click on the links.
Current Long-term Drought Status
Long-term drought uses the 24-month (April 2019-March 2021), 36-month (April 2018-March 2021) and 48-month (April 2017-March 2021) Standardized Precipitation Evaporative Index which takes into account precipitation and evaporation due to temperature. Long-term drought reflects water resources related to streamflow, aquifer recharge and reservoir storage. The previous two- and three-year periods were quite wet; the current winter had been quite cold, leading to reduced evapotranspiration, though April was warmer than normal, increasing evaporation and drying out soils. Long-term drought is virtually unchanged since March as April was dry, but April is normally a relatively dry month.
Posted May 2021
The next long-term drought update will be posted in early June.