Current Conditions

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Update on the California Drought: :  October 12 – November 7, 2016

From the Pacific Institute’s California Drought Response Team

Top Story

Drought Conditions Improved, But the Shadow of La Niña Looms

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.

In Other News

  • Urban water use for September 2016 was 18.3% less than water use for September 2013. This value represents an eight-percentage point drop from the September 2015 water savings of 26.2%. Houeshold water use was highest in the Colorado River region, at 188 gallons per person per day. The San Francisco Bay and the North Coast regions had the lowest household water use, averaging about 80 gallons per person per day.
  • A study by researchers at Cornell University found that the risk of megadrought in the Southwestern United States may increase to 99% by the end of this century if temperatures continues to rise.
  • The Department of Water Resources (DWR), Cal Fire, and the National Weather Service (NWS) warned of the potential for flash flooding during the rainy winter months. Areas affected by wildfires are at a higher risk of erosion and flash floods during a period of intense rainfall because vegetation has been burned away and bare grounds tend to repel water.
  • A recent report by the Bay Institute entitled “San Francisco Bay: The Freshwater-Starved Estuary” shows that large-scale water diversions in the Bay’s watershed have exacerbated drought impacts on ecosystems and caused the Bay to be critically dry in 19 of the last 30 years.
  • Researchers at the University of California, Los Angeles, and Oregon State University have concluded that greenhouse gases played a role in the record-low 2015 snowpack in California. Through regional climate model simulations, the study showed that both human influence and sea surface temperature anomalies contributed to the risk of snow drought, or periods of a lack of snow, in California. This correlation is even stronger in Oregon and Washington.
  • A mass of unusually warm water, also known as “the Blob,” has moved into the northeastern region of the Pacific Ocean. Since 2014, it has worsened drought impacts on anadromous fish (e.g., salmon) and other marine species by disrupting the ocean food chain and creating conditions that have led to toxic algal blooms along the coast of Western United States.
  • Scientists have detected high levels of a freshwater algae toxin known as microcystin in shellfish in the San Francisco Bay. Microcystins are produced by the blue-green algae that is blooming in many of California’s waterways, partially because of the drought.

 

California Drought Status

Drought Monitor

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.

Precipitation

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.

Reservoir Conditions

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:

  • The water level at Lake Shasta is at 105% of the historical average. Lake Oroville and Folsom Lake are at 73% and 76% of the historical average, respectively.
  • The water level at the New Melones Reservoir, another major reservoir with a 2.4 million acre-feet capacity, is at 38% of the historical average.
  • The water level at the San Luis Reservoir hit its lowest level in 27 years in mid-August and now stands at 59% of the historical average for this date.
  • Lake Cachuma, which supplies water to the city of Santa Barbara and other urban areas in Southern California, remains very low at 7% of its capacity, or 10% of the historical average.

Wildfires

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

Hydropower

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.

Groundwater Conditions

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.

Additional Resources

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