In the wake of a series of destructive storms in late December and early January, California’s long-ailing mountain reservoirs have risen, satellite images from NASA show.

Lake Oroville, which sits in the northern reaches of the Sierra Nevada mountain range, was at just 28 percent of capacity in late November and is now at 69 percent capacity, following the winter deluge. Long depleted by drought, the reservoir is now close to its historical winter level. Lake Shasta, in far northern California, was at just 31 percent of capacity in late November and is now at 58 percent capacity, bringing it in line with the historical average.

Recent storms “certainly helped reservoir storage in California following the driest three years in the state’s recorded history,” Jeanine Jones, an official with the California Department of Water Resources, told the Los Angeles Times. “Over the next two months, it is important that we still see periodic rain and snowstorms to keep an above-average pace for our precipitation totals.”

Experts warn, however, that recent storms will likely do little to ameliorate long-term shortfalls. While this winter’s snow and rain will help recharge stores of groundwater in the near term, “if the climate pattern is the same as before — dry and hot in summer followed by low precipitation — and the water demands are still high, then we expect the groundwater drawdown will continue,” Pang-Wei Liu, a NASA scientist involved in groundwater monitoring, said in a statement.

A recent study found that the drop in groundwater in California’s Central Valley has accelerated over the last two decades. “The years 2000–2021 represent the driest 22-year period since at least 800,” authors wrote. They highlighted the need for better management of groundwater “to ensure its availability during the increasingly intense droughts of the future.”

ALSO ON YALE E360

A Quiet Revolution: Southwest Cities Learn to Thrive Amid Drought