As California digs itself out from staggering accumulations of snowfall, there has been a pressing question in the minds of many: Could the near-record levels of snow be enough to fill the state’s reservoirs and break the drought that has long strangled the region?

That depends on something called snowpack, which is essential to refilling the state’s reservoirs. And, indeed, snowpack in the Sierra Nevada mountains is creeping toward record levels, Karla Nemeth, director of the California Department of Water Resources, said in a statement. But, she added, “it will also take more than one good year to begin recovery.”

(The drought in the western U.S. could last until 2030. Here's why.)

So what exactly is snowpack,