Weather experts in California upgraded the state's drought intensity from a D3-Extreme Drought to D4-Exceptional Drought for all of San Luis Obispo and Santa Barbara Counties, and half of Ventura County.
The decision is made jointly by the Department of Agriculture and NOAA -- National Oceanic and Atmospheric Administration.
The explanation below comes from The National Drought Mitigation Center and explains the reason for the increase in drought status.
Southern California missed out on both week's precipitation while unseasonable warmth persisted, further degrading conditions similar to the Southwest. With WYTD precipitation running at a meager 10-30% of normal across coastal southern California and deficits of 4-12 inches the past 6-months, D3 was extended southward into the San Diego area, and D4 was expanded southward into Santa Barbara and Ventura Counties. In Santa Barbara County, Lake Cachuma, currently at 39% capacity and 90% of the water supply for the cities of Santa Barbara and Goleta, the water level is nearing the lowest intake on the outlet works. To remedy this, the water district is working on installing a floating barge and pipes to get lake water to the outlet portal. The city is also contemplating the re-establishment of a desalination plant built in the late 1980s that was shut down in the early 1990s. And the Twitchell Reservoir, along the Santa Barbara/San Luis Obispo County line, is at less than 1% capacity. Ranchers are reducing their herds due to the lack of water and food sources. As of Feb. 18, the Sierra Nevada basin average snow water content ranged from 32 to 53% of normal. Widespread heavy precipitation is badly needed in this state as the normal wet season nears its end by early to mid-spring (e.g. in April).