Why California is still in drought despite heavy rain and snow

Climate change

Despite recent storms, the golden state is still in a long-term dry spell.

Snow blanketed California the last weekend of February, only weeks after it was pummeled by torrential rains. But these historic storms barely made a dent in a daily reality for most Californians — a years-long, expansive drought. According to the U.S. Drought Monitor, 99.39% of the state is still abnormally dry or in drought: crops wither, water supplies dwindle, and wildfire risk intensifies as forests dry out.

Recent rain has given reservoirs a much-needed boost. But the storms have been intense and concentrated, and the state’s water infrastructure, mostly built in the 20th century when the population was barely half of today’s 40 million, is ill-equipped to harness such massive rainfalls.

Short storms, however strong, are not enough to end California’s drought.

The heatmap on the left shows drought severity and coverage index data for each county in California from October 2000 to January 2023, broken up into smaller sections by time periods. One rectangle represents one week of drought data for one county. The darker the rectangles, the more severe the drought. Light-colored rectangles represent relatively wet weather. Counties are organized by geographical location, with northern counties on the left and southern counties to the right.

The area chart on the right shows total monthly precipitation in California over the same period, and the line represents monthly precipitation averaged over 1895 to present.

The drought heatmap and precipitation charts below show data for October 2000 to October 2002.

California’s land is parched. Since 2000, it has cycled through four periods of drought, which occurs when unusually dry weather and lack of rain persist for two or more years.

Crops can withstand short-term dry spells because they are irrigated. But forests and other natural ecosystems are more vulnerable because they don’t have extra water reserves — and this heightens the risks and severity of wildfires.

Devastating fires swept through the state in 2003 during the 2001–2004 drought.

In the Cleveland National Forest, a hunter became lost and lit a small fire to signal for help. It spread out of control and became, at that point, the largest wildland fire in California’s history. The loss from the Cedar Fire was estimated to be $204 million.

The charts below show drought and precipitation data for October 2002 to October 2004. The area highlighted red shows the Cedar Fire.

California tends to cycle through periods of wet and dry weather. After the 2001–2004 drought, the state got a reprieve with a few years of higher-than-average rainfall:

The charts below show drought and precipitation data for October 2004 to October 2006.

After about two years of wet weather, California entered another drought. During the 2007 water year — which starts in October 2006 and ends in September 2007 — total precipitation in Southern California was less than one-third the average. In Central California, it was less than half.

External factors exacerbated the impacts of the 2007–2009 drought: intrastate water projects were restricted to protect endangered fish species, which reduced water supplies. Because of the water shortages, workers and people in rural communities dependent on agriculture lost jobs.

In 2009, the governor declared California’s first statewide emergency for drought.

The charts below show drought and precipitation data for October 2006 to October 2009.

The 2007–2009 drought ended as California entered another period of wet years:

The charts below show drought and precipitation data for October 2009 to October 2012.

In 2012, one of the longest droughts in recent history hit the state. It lasted for five years.

Drought-related losses totaled an estimated $10 billion. When groundwater wells dried up, communities with smaller water systems that lacked emergency supply suffered. In 2015, almost 2,000 domestic wells — privately-owned sources that many people in rural areas rely on for everyday needs — failed in Tulare county alone. People there had to haul in water for everything, from drinking to bathing.

Years of relentless drought took a toll on trees, too. Weakened by drought, high temperatures and bark beetle infestation, 26 million trees died across 6 counties in just 8 months.

The charts below show drought and precipitation data for October 2012 to October 2016.

During the 2016 water year, precipitation returned to near normal in Northern California, which alleviated the impacts of drought for many counties. But Southern California remained dry.

Heavy rainfall — which made 2017 the state’s second wettest year on record — finally ended the five-year drought.

The charts below show drought and precipitation data for October 2016 to October 2019.

Less than four years later, California entered yet another drought in 2020. By the end of 2022, the state had weathered its driest three-year period on record.

Interspersed were record-breaking storms that dumped massive amounts of rain and snow on the state — a whiplash from dry to wet. And the two climate extremes are becoming even more drastic: as droughts and heat waves intensify, massive storms are expected to deluge the state during its occasional wet years.

The two extremes can torment California at the same time. During the barrage of winter storms in late 2022 and early 2023, the state declared a state of emergency for the flooding and water destruction.

At the same time, it remains in a drought emergency issued by governor Gavin Newsom in 2021.

The charts below show drought and precipitation data for October 2019 to January 2023. The area highlighted red shows the August Complex fire.

Climate change and warmer temperatures will only make drought more severe. The year 2014 was the hottest on record for California, making the 2012–2016 drought one of the warmest in history.

California average temperature

A hotter future will gradually reshape our water cycle. Plants and soil will be thirstier and guzzle more water, reducing water supplies. Snowpack is already melting earlier than usual. Precipitation types will change — areas that receive snow will see more rain — and as a result, water that was once stored as snowpack will run off.

Even with this year’s heavy rainfall, long stretches of dry weather following on the heels of storms mean it’s uncertain whether California will be able to escape the current drought.

“I think we did get enough to get through the year,” says California state climatologist Michael Anderson. But, Anderson says, it’s still too early to say if the storms contributed to “the true end of the drought or just a really tough way to alleviate conditions — but not completely remove them.”