From Parched to Pouring: Can the 2015 – 2016 El Niño Event Bring Drought Relief to California and the Western U.S.

Abstract:

Water resource managers throughout the Western United States have struggled with persistent and severe drought since the early 2000s. In California, a historic 4-year drought period has resulted in just under 50% of the state experiencing exceptional drought conditions, and record low snowpack levels in the Sierra Nevada region; additionally, the drought has cost the California agricultural community approximately $3 billion in losses. In the Colorado River Basin, nearly 80% of the basin is in drought, as record low levels at Lake Mead threaten to impose the first ever water shortage in the Lower Colorado River Basin and threaten a portion of the nearly $960 billion economy dependent on water from the Colorado River. The El Niño Southern Oscillation (ENSO) describes warming sea surface temperatures in the Pacific Ocean that typically correlate with cool and wet precipitation events in California and the Lower Colorado River Basin during an El Niño event. Past research indicates the potential to identify analog ENSO events to evaluate the impact to water resources in the Western U.S. Two of California’s wettest winters have occurred during the strong El Nino events of 1982 - 1983 and 1997 – 1998. The 1982 – 1983 event also corresponded with one of the wettest years on record in the Colorado River Basin. Current forecasts indicate the potential for one of the strongest El Niño events on record this winter.

In this study, remotely sensed precipitation is utilized and compared to past ENSO events in an effort to identify possible hydroclimatic and water supply impacts to California and the Colorado River Basin. Western U.S. snowpack and precipitation events are further compared to streamflows in the region and the potential for extreme (i.e., flooding) events in an effort to inform water resource managers throughout the Western U.S.