Snowfall in California Went a Long Way to Helping the State's Drought

In just about a month, over a third of drought-stricken, wildfire plagued California’s snow-water deficit has been restored. Aided by NASA satellite data, CU Boulder’s Center for Water Earth Science and Technology (CWEST) found that two storms in December and January produced enough precipitation to restore 37% of the five-year deficit in snow-water.


“The start to winter has been the best California has seen since 2011 and gives water managers hope for relief from what has been a historically dry five-year period,” said David Rizzardo, Chief of Snow Surveys and Water Supply Forecasting for the California Department of Water Resources.

Rainstorms are probably the first solution that comes to mind for a drought as sustained and severe as California’s, but snow is actually preferable because it falls slower and refills reservoirs more gradually, lessening the chance of flooding. Unfortunately, that was exactly what happened in July 2015, when a sudden rainstorm caused massive flooding throughout the state, even as other areas caught aflame because of drought.

Yet although the snow is welcome, researchers say too much could lead to more flooding. “The concern moving forward relates to what happens with the weather for the rest of the winter,” said Noah Molotch, director of CWEST and a research associate at CU Boulder’s Institute of Arctic and Alpine Research (INSTAAR). “Reservoirs across the Sierra foothills are now relatively full and if we get another intense atmospheric river with warmer air temperatures, the risk for rain-induced flooding is considerable.”

It’s good news, but it’s well worth noting that the state’s not out of trouble yet. In 2014, NASA estimated the ongoing drought put California in an 11-trillion gallon overall water deficit, and there’s still been a great deal of damage done to farmlands and once lively forests.

“When the snow stopped falling five years ago, the state had to tap into its groundwater reserves to keep up,” said Moloch. “One snowy winter won’t be able to entirely reverse that, but there is, at least, some cautious optimism.”



Of course I have pages. I had pages five years ago. How anyone can believe I don’t defies belief.



To build off that last point: subsidence from the extreme degrees of groundwater pumping mean that even if this winter and the next two years fill reservoirs and eliminate the drought, the amount of available groundwater for future droughts will be permanently (as far as our time scales are concerned) reduced.

What California does over the wet years to prepare will determine how, and if, they can handle future droughts.