A series of torrential California storms dented drought

Atmospheric rivers that have pounded California since late last year have covered mountains in winter snow and begun to raise reservoir levels, but experts say it will take much more rain to reverse the effects of years of drought.

A weekly update from the US Drought Monitor, published Thursday, showed that the “extreme” drought was all but eliminated a week after the worst category – “exceptional” – was wiped off the map. Two weeks ago, a severe drought covered 35% of California.

The Drought Monitor described the improvement as a significant reduction in drought intensity, but warned that large parts of the state are experiencing moisture deficits that persist for two or three years.

Most of the state is currently in the “severe” or “moderate” drought category, with small areas in the far northwest and far southeast being described as “abnormally dry”, the lowest level.

After significant damage to some communities and at least 18 deaths in California, there was a lull between storms on Thursday, but further precipitation was expected on Friday and continued through the weekend. Flooding remained a problem, especially along the Salinas River in Monterey County, because so much rain fell.

In downtown San Francisco, for example, nearly 13.6 inches (34.5 centimeters) of rain fell between December 26 and January 10. Snowfall this season at the summit of the Mammoth Mountain resort in the Eastern Sierra has reached 444 inches (11.3 meters). .

In the Sierra Nevada and other mountains, snowpack water content is more than 200% of the norm today and more than 100% of the April 1 average, when it is historically at its peak, according to the State Department of Water Resources. .

“Automatic sensors are recording what they believe is full seasonal snow cover, what we expect on April 1st,” state climatologist Michael Anderson told reporters this week.

Snow cover provides about a third of California’s water when it melts and drains into rivers and reservoirs.

At the local level, some reservoirs have experienced a significant increase in water levels, but a significant deficit has yet to be overcome.

Across the state, reservoir volume is only 82% of the average for this time of year. The largest reservoir, Shasta, is only 44% full. This is only 70% of the average today. The huge Oroville reservoir is closer to its average, but it has only 49% capacity.

California’s historic rainfall is an example of what’s called a weather whip, raising questions: Can there be a drought in the midst of a flood? Has all this rain wiped out the drought? Explains David Simeral of the Desert Research Institute. (January 12, 2023)

“The good news is that they are off the all-time low,” Anderson said of the large reservoirs. “The problem is that they still have a lot to recover before they return to normal operating conditions.”

And there are fears that the rains could stop abruptly. The end of 2021 was marked by severe storms, but at the beginning of 2022, the months were completely dry.

There are some hints that a drier pattern will develop around January 20, Daniel Swain, a climate scientist at UCLA, said during an online briefing this week.

AP reporter Olga R. Rodriguez contributed from San Francisco.