How Much Rain is Needed to End a Drought? Not Enough For the Southwest U.S.

The recent record-breaking rainfall in the Southwest United States will not eliminate the region's long-term megadrought status, researchers say. The extra moisture fueled by atmospheric rivers and an El Niño weather pattern has eased parched conditions somewhat.

However, drought persists in areas and the rain has not significantly replenished critical water sources.

Multi-decadal precipitation deficits preceded the current wet period. Returning regional water availability to normal levels would require many more years of ample rainfall.

The rainwater has also done little to bolster supplies for major Southwestern cities. These population centers rely heavily on snowmelt from the Colorado River Basin. That watershed remains drought-stricken.

Recent Years of Heavy Rainfall After Prolonged Dry Period