The latest winter storms were a big boost for California — for the first time since January 2014, no part of the state is in the worst category of drought, just 2 percent of the state is now in extreme drought, and almost 50 percent is no longer categorized as being in drought.
That’s according to new data released Thursday by the U.S. Drought Monitor, a weekly report and map produced by the National Oceanic and Atmospheric Administration, the U.S. Department of Agriculture and the National Drought Mitigation Center.
Richard Tinker, a drought expert with the National Weather Service and the author of this week's drought map, said the weekend's epic rainstorms led him to downgrade much of Southern California to lower levels of drought severity.
"Precipitation has been so copious this month that it’s affecting long-term precipitation deficits, bringing some alleviation to the (drought) impacts," he said.
Tinker considers several different indicators to determine the various degrees of drought: soil moisture, rainfall and streamflow. In California and the West, they also use snow water content, groundwater and reservoir storage.
"California is one of the more complicated states" to rank given how much we move water around the state, and how erratic our precipitation is, Tinker said. "I would say most of the rest of the country is less complicated than California is."
There are a few areas of Southern California, mostly in Santa Barbara and Ventura counties, still facing extreme drought conditions even though they, too, received a lot of rainfall recently. How can this be?
According to Tinker, it's easy to be misled by the wet weather.
"The tendency is for people to say there is no drought," he said. "What we find happens is given the deficits that accumulated over a long period of time, the region is primed to dry back out more than it normally would be. You can have short-term flooding without completely ameliorating a long-term drought."
Tinker decided to keep Santa Barbara and Ventura counties in extreme drought because they are much more reliant on local sources of water than residents of greater Los Angeles, which was downgraded to severe drought.
Ventura, for example, doesn’t import water from the Sierra Nevada or the Colorado River like the rest of the region, so it is more dependent on groundwater, reservoirs and rainfall. Lake Casitas, an important reservoir in Ventura County, is 37 percent full after the weekend storm. And Lake Cachuma in Santa Barbara is just 12 percent full.
Meanwhile, greater Los Angeles can import water from hundreds of miles away. The decreased vulnerability of the area's water supply factored into Tinker's decision to call that area a severe drought instead of extreme.
But it’s good to keep in mind that not all experts agree on the status of California’s drought.
The state Department of Water Resources argues that the "severe" designation doesn’t take into consideration all the imported water Southern California gets. The Los Angeles Department of Water and Power, for example, imports nearly 90 percent of its water from the Sierras and the Colorado River. So the area may be in a "severe drought," but its water supply is still secure as long as there is enough snowfall in the Sierras and in the Rockies.
But here’s one thing the drought monitor does do: it takes into consideration the larger California ecosystem, not just our needs. The drought monitor looks at the conditions of wildlands outside of cities, and locally a lot of those areas are still still suffering. Consider the 100 million trees that have died since 2010. For them this rain is too little, too late.