Major Snowfall in California Not Sufficient To Offset Chronic Megadrought Effects, Study Reveals

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Even though California has seen winters that are heavy in snow, the Sierra Nevadas' snowpack was not sufficient in curing the dry soils of the state.

In fact, satellite data has shown that California's recent major snowfall was not sufficient to offset the chronic impacts of the megadrought faced by western states.

Snowfall Not Enough To Offset Megadrought Effects

This was noted in the "Snowfall Replenishes Groundwater Loss in the Great Basin of the Western United States, but Cannot Compensate for Increasing Aridification" study.

The insufficient recovery of groundwater supply, despite the massive levels of snowfall, is quite concerning for both domestic and agricultural water use. Data taken from GRACE (Gravity Recovery and Climate Experiment) satellites showed that groundwater supply in the entire Great Basin of the western US has gone down by 16.5 cubic miles in the last two decades.

Data has also revealed that though snowmelt indeed helps with refilling the water, it is not sufficient to replenish groundwater levels completely.

Earth scientist Dorothy Hall, a co-author of the study from the University of Maryland, noted that in times like the winter of 2022-2023, it was expected that record snowfall amounts could aid in replenishing groundwater supply. However, decline generally went on.

California and other southwestern states have faced megadrought grips since the millennium's dawn due to climate change. This drought has led to the whittling away of the soils and reservoirs, which are crucial water sources for consumption and agriculture.

On April 1, 2023, the Sierra Nevada snowpack had a 232% average for the date, making it the highest levels seen since 1952. Moreover, various years since 2010 have seen snowfall levels in winter that were above average. These years included 2017 and 2019.

However, the new study showed that groundwater in the Great Basin did not recover after such massive snowpacks. Hall notes that one primary reason for the decline is the upstream diversion of water for households and agriculture.

With persisting drought threat, farmers in downstreat may not get sufficient water. Ultimately, the solution must cover wiser management of water.

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Megadrought

Jonathan Overpeck, the environmental studies dean from the University of Michigan, noted that a megadrought goes on for at least two decades. Currently, the southwest megadrought began in 1999 and has turned to be US history's longest drought. This was also the most severe one in the last 1,200 years.

Though previous droughts have resulted mostly from a precipitation reduction, the persisting southwest megadrought is as much a global warming product that comes with rain and snow decreases. Such warming is caused by human-induced climate change, which is primarily driven by burning fossil fuels.

The megadrought has also yielded great effects on flows of major rivers in the southwest, particularly the Rio Grande and the Colorado River. It is also causing a growing water crisis within the southwest.

It was hoped that the high snow levels that fell in the Sierra Nevada in the past couple of years could help replenish this deficit in groundwater.