Storm after storm has pummeled California over the past few weeks as a series of so-called atmospheric rivers has come ashore. Given the massive amounts of rain and snow that have fallen, people want to know if California's five-year-long intensive drought is finally over.

WIRED OPINION About Peter Gleick (@petergleick) is co-founder and chief scientist of the Pacific Institute, a hydroclimatologist, and a member of the US National Academy of Sciences.

The answer, of course, depends on what people mean by "drought" and "over," and it depends on who you ask. There isn't—and never has been—agreement about the meaning of either word.

Drought is defined and used in many ways: There are meteorological, hydrological, agricultural, and socioeconomic droughts. The National Drought Mitigation Center defines drought as originating from "a deficiency of precipitation over an extended period of time—usually a season or more—resulting in a water shortage for some activity, group, or environmental sector. Its impacts result from the interplay between the natural event (less precipitation than expected) and the demand people place on water supply, and human activities can exacerbate the impacts of drought."

Common drought indicators evaluate the balance between the water that comes into the state, via rain and snow, and the water that goes out in runoff, consumption, and evaporation. By any measure, California's five-year drought, from 2012 to 2016, was extreme. Indeed, precipitation, runoff, and soil moisture in the Sacramento and San Joaquin river basins have been far below normal for a long time.

So far, this water year, which began October 1, is different. The chances are excellent that rain, snow, and runoff will be far above average. At this point in January, Northern California has already received almost its entire annual average precipitation, the snowpack is at 150 percent of normal, and reservoirs are filling up. The abundance of rain and snow so far this year led the National Drought Mitigation Center to conclude that the drought in northern California is over.

True, the wet parts of the water year are not over yet, but the firehose of moisture hitting us from the Pacific could also still dry up. And the relative abundance of water will bring calls to increase deliveries of water to cities and farms and to remove urban conservation restrictions.

But another key variable is temperature. Temperature determines, among other things, the demand for water by crops, vegetation, and people, and especially the ratio of snow to rain that falls in the mountains. The past five years were by far the driest and hottest in more than a century of recordkeeping—in part because of human-caused climate change—and those high temperatures played a key role in worsening the scarcity of water and devastating the snowpack. This combination of hot and dry led to massive groundwater overdraft, cutbacks to farmers, loss of snow storage in the mountains, reductions in hydropower production, and a range of voluntary and mandatory restrictions on urban water use. And while the wet year may end the "precipitation drought," higher and higher temperatures and a persistent "snow drought" are here to stay.

Worst of all, these hydrological and meteorological measures don't tell the whole story. Even in a wet year in California, nature's bounty of water is no longer enough to satisfy all the state's demands, recharge overdrafted groundwater basins in the San Joaquin valley, or overcome the massive deficits suffered by California's ecosystems and endangered fisheries. Far more water has been claimed on paper than can ever be reliably and consistently delivered to users. If the most straightforward definition of drought is the simple mismatch between the amounts of water nature provides and the amounts of water that humans and the environment demand, California is in a permanent drought.

Whether or not the drought is officially declared "over" and emergency restrictions are lifted, we must still face up to the fact that our water system is out of balance, even in a wet year. Demands exceed supply, disadvantaged communities don't have reliable access to safe water, ecosystems are dying, and our water systems are unsustainable and poorly managed. And in the context of a changing climate, these problems will only worsen.

The good news is that the last five years have shown that California can still have a healthy economy and a strong agricultural sector if we work to improve our use of water, cut inefficient and wasteful practices, and expand the use of non-traditional sources of water, especially including better stormwater capture and expanded wastewater treatment and reuse. Relatively painless urban conservation programs, such as appliance efficiency programs and efforts to replace turf with drought-resilient gardens, saved more than 2.3 million acre-feet of water just between June 2015 and November 2016, enough to provide 20 million people with their residential water needs for a year. The California agricultural sector suffered only modest decreases in production and employment and saw record high revenues during the drought while becoming more efficient.

Ultimately, "is the drought over?" is the wrong question. We should be asking, "are we managing our water resources in a sustainable manner, for the long haul"? The answer to that is still "no."

The drought has forced us to think differently about water, to learn new lessons about how to make do with less water. Half a century ago, John Steinbeck wrote in East of Eden: "And it never failed that during the dry years the people forgot about the rich years, and during the wet years they lost all memory of the dry years. It was always that way." We now have an opportunity to prove him wrong, to remember even in wet years that the lessons learned in dry years can stay with us.