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From the Pacific Institute’s California Drought Response Team
October rains have brought some relief, especially in the northwestern parts of the state, including Humboldt, Del Norte, Siskiyou, and most of Trinity and Shasta counties. According to the U.S. Drought Monitor, 12% of the state is no longer experiencing drought conditions, the highest percentage of drought-free area since March 2013. However, about 43% of the state is still experiencing extreme-to-exceptional drought, unchanged from three months ago.
Satellite images from September and October 2001 and the same months in 2016 reveal the drought’s toll on ten California reservoirs. Scientists have warned that it will still take several years of above-normal precipitation for soil moisture levels, reservoirs, and groundwater aquifers to recover.
At the same time, a new forecast by the National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center suggests that the likelihood of La Niña, a climate pattern linked to drier weather in California, has increased. There is now a 70% chance that La Niña will develop in the fall of 2016 and a 55% chance that it may persist during the winter of 2016/2017.
While 43% of the state remains in extreme-to-exceptional drought, important changes have occurred in the northwestern parts of California as of November 1, 2016. Areas affected by moderate-to-severe drought conditions have declined from 41% to 32% of the state over the past month. About 12% of the state is now identified as drought-free, namely Del Norte, Humboldt, Siskiyou, and most of Trinity and Shasta counties.
The NOAA’s October forecast indicates that La Niña has a 70% chance of developing this fall, and a 55% chance of persisting during the winter of 2016/2017. This new prediction brings back concerns about continued drought conditions.
The new water year began on October 1, 2016. A 3-month precipitation outlook (Dec-Jan-Feb) shows a normal precipitation pattern for Northern California, but a slightly below average precipitation for Southern California.
After the October rains, water levels in California’s major reservoirs (representing 27.3 million acre-feet of storage) have increased by one percentage point to 44% of the statewide capacity compared to a month ago. Current storage levels represent 81% of the historical average for this time of year, five percentage points higher than the previous month. Conditions in individual reservoirs vary across the state, with those in the north continuing to do better than those further south. For example:
Since the beginning of 2016, a total of 7,206 wildfires have burned over 560,000 acres across the state. There are currently 10 active wildfires in California, according to InciWeb, a national all-risk incident information management system. All the largest active wildfires (over 8,000 acres) are fully contained.
Please note that wildfire data are preliminary and may change. They are updated daily by the National Interagency Coordination Center
Hydroelectric power generation in August 2016 was about 2,800,000 MWh, representing a 70% increase over last year’s August production of 1,700,000 MWh. However, hydropower generation is still 16% below the 2001-2011 average for the same month.
The most recent data on groundwater conditions are based on measurements taken in spring 2016. Maps of spring and fall groundwater level changes can be found here. Parts of the Tulare Lake, the South Coast, and the Colorado River hydrologic regions have experienced groundwater declines of more than 100 feet between fall 2011 and fall 2015.