After a massive rainstorm, California and Nevada are no longer experiencing a "extreme drought."

 Jan 5, 2023 

Two states' drought conditions have improved as a result of the violent storms battering the drought-stricken West Coast, but the torrent of rain is unlikely to end the region's decades-long acute drought.

According to data released by the U.S. Drought Monitor on Thursday, areas of California and Nevada that were previously classified as "exceptional drought" no longer merit the highest level of concern because of the severe storms that are bringing an influx of rainfall to the region and are being sparked by atmospheric rivers.

According to the Drought Monitor, the recent unexpected onslaught of rain has caused California to experience 0% exceptional drought, 27% extreme drought, and 71% severe drought, while Nevada is experiencing 0% exceptional drought, 24% extreme drought, and 78% severe drought. The rain that fell overnight on Wednesday is not included in the most recent Drought Monitor statistics.

According to the Drought Monitor, California experienced a nearly 1% exceptional drought last year, while Nevada experienced a nearly 8% exceptional drought.

In the 24-hour span from Wednesday morning to Thursday morning, some of the greatest rainfall totals were 5 inches in Potter Valley, north of the Bay Area, almost 4 inches in Valley Christian, south of San Francisco, and 4.67 inches in Los Angeles County. Due to the floods that resulted, major cities including San Francisco and Los Angeles had power outages on Thursday morning that affected almost 175,000 Pacific Gas and Electric Company customers.

On Thursday, when bouts of heavy rain were anticipated to continue, around 90% of Californians were under a flash flood watch. According to officials, at least two Sonoma County residents died in storm-related collisions on Thursday.

For the mountains outside of Los Angeles, where up to a foot of snow is forecast, a winter storm warning was in force on Thursday.

The amount of moisture has increased so dramatically that San Francisco has received 10 inches, or half of its annual rainfall total, in the last 30 days.

But scientists predict that it would take many seasons with 120% to 200% the usual rain and snowfall to end the West's drought. Amir AghaKouchak, a professor at the University of San Diego who specialises in hydrological extremes and drought monitoring, told ABC News that it was a difficult achievement given the anthropogenic — or human-induced — warming several states in the West, including California and Nevada, are experiencing.

The risk of shifting from severe drought to inundating seasons increases, according to experts, as climate change threatens to make extreme weather events more frequent and last for shorter periods of time.

According to AghaKouchak, there are "many aspects" to drought, and climate change is predicted to modify how closely the West's drought and flooding are related.

"We predict more extreme droughts, perhaps longer droughts, or more frequent droughts in a warmer environment," he added. "However, we anticipate additional severe precipitation occurrences at the same period."

AghaKouchak said that it is also common for circumstances to quickly change from flood to drought and back again. The burn zones left behind by the devastating wildfires that have scorched significant portions of the Western United States are ideal spots for mudslides to happen. The quick flood of water cannot be contained by the dry ground, which then combines with the sediments to produce potentially fatal conditions.

Snowfall may have a significant influence on water resources when it melts in the spring, despite the fact that lack of rainfall is the main cause of drought. According to AghaKouchak, the groundwater supplies are almost completely drained, and the recent rainfall is not doing anything to replenish them.

The storms currently affecting the West Coast will also do nothing to relieve water restrictions in areas farther east that depend on Lake Mead and Lake Powell, the two biggest reservoirs in the nation that receive water from the Colorado River.