California-Nevada Drought Status Update

Early Winter Check-In: Drought Remains with Areas of Improvement

Key Points

California and Nevada are entering the climatological wettest three months of the year 100% in drought.
An exceptional atmospheric river (AR 5) in October helped relieve some of the drought, but a dry November still has much of the region missing 0.5–1.25 years of precipitation.
Snowpack and soil moisture have improved in areas receiving recent rain and snow.
Although a wet pattern is favored for the remainder of December and drought conditions are forecasted to improve in parts of central and northern California, more precipitation is needed and drought remains region-wide.
Both the governors of California and Nevada made drought announcements in December bringing attention to the importance of drought preparedness.

U.S. Drought Monitor Conditions | December 14, 2021

California-Nevada

The U.S. Drought Monitor (USDM) is updated each Thursday to show the location and intensity of drought across the country. Drought categories show experts’ assessments of conditions related to dryness and drought including observations of how much water is available in streams, lakes, and soils compared to usual for the same time of year.

California/Nevada conditions as of December 14, 2021:

100% of California is experiencing Moderate (D1) to Exceptional (D4) Drought (52.01% in D3, 28.27% in D4)
California population in drought: 37,253,956
100% of Nevada is experiencing Moderate (D1) to Exceptional (D4) Drought (31.44% in D3, 24.89% in D4)
Nevada population in drought: 2,700,551

Source(s): NDMC, NOAA, USDA

U.S. Drought Monitor Categories

Last Updated: 12/14/21

100%

of California and Nevada are in drought (D1–D4)

80.28%

of California is in extreme to exceptional (D3–D4) drought

56.33%

of Nevada is in extreme to exceptional (D3–D4) drought

Current Conditions

According to the U.S. Drought Monitor, since the start of the water year (Oct. 1, 2021) drought has improved in parts of northern California and Nevada, but the region remains 100% in drought.
A warm and dry November followed October’s exceptional atmospheric river (AR5) that brought widespread rain, snow, and wind to parts of the West, leaving much of the region yet missing 0.5–1.25 years of precipitation.
Following a series of storms in mid-December, California’s overall snow water equivalent (SWE) jumped from from 18% of normal on December 1 to 83% of normal on December 15 based on California Department of Water Resources snow pillows; most of this increased snowpack has come between December 13–15 as several storms slammed into the Sierra Nevada.
Over the last three days, December 14–16, the atmospheric river increased the 8-station index by 5% of the end of year water year normal precipitation, approximately a 9% increase in Los Angeles and San Diego, and an 8% increase for the Reno/Carson City Area.
Beneficial precipitation has improved soil moisture conditions and reservoir levels, although many remain below their historical averages.

How Is Drought Impacting Your Neighborhood?

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U.S. Drought Monitor Change Map: Water Year To Date

U.S. Drought Monitor Change Map for the California Nevada River Forecast Center region, showing the change in drought conditions from September 28, 2021 to December 14, 2021. Parts of northern California and Nevada have seen a 1 to 2 category improvement, but drought persists in 100% of the region. — U.S. Drought Monitor change map, showing how drought has degraded or improved since the start of Water Year 2022, from September 28 to December 14, 2021. Source: National Drought Mitigation Center.

Percent of Normal Precipitation: Water Year to Date

The image shows the percent of normal precipitation for California and Nevada over 10/1/2021 - 12/15/2021. County outlines are shown with a color bar from <5% (red) to >300% (pink). Southern California-Nevada remains with less than normal precipitation compared to other parts of the region. — Percent of normal precipitation since the start of Water Year 2022 (October 1–December 15, 2021). Source: High Plains Regional Climate Center.

Precipitation Anomalies Since October 2019

A map of California and Nevada showing the missing or excess number of years of precipitation as of September 30, 2021 based on normal (1981-2010 average) water year precipitation (left) accumulated October 2019 through September 2021 and (right) accumulated October 2019 - December 1 2021. The color bar ranges from red (-2 years) through blue (0 year). Much of California and Nevada are missing more than 0.5 years of precipitation ending in September 2021. Northern California and Washoe County are missing over a year’s worth of precipitation. The years of missing precipitation decreased in northern California and northwestern Nevada indicating beneficial the impact of precipitation in October to the total precipitation deficit of the ongoing drought. — The number of normal (average) water years' worth of precipitation accumulated October 2019–September 2021 (*left*) and accumulated October 2019–December 1, 2021 (*right*). The difference shows the impact of the AR5 that made landfall in October. Figure provided by M. Dettinger, CNAP and PPIC.

Total Precipitation: November 2021

A map of California and Nevada showing the total precipitation through November 2021. The color bar ranges from brown (0-1 inch) to green (7-8 inches). All of Nevada and all of Central and Southern California received less than 1 inch of precipitation in November. Only the far northwestern corner of California received 7-8 inches. — The total precipitation (inches) in November 2021 throughout California and Nevada. Source: Climate Toolbox.

Reno/Carson City Percent of Normal Precipitation

Graph shows the percent of normal (mean) accumulation for the water year for the Reno/Carson City area. The black line is showing the 2021-2022 water year with the percentage for the current water year annotated at 56.5%, the dashed blue line shows the mean which for this time of year is 23.7% and, the dark blue shading shows the middle ⅔ of years which ranges between 11-38%, and the cyan shows the range of all the years. — Graph shows the percent of normal (mean) accumulation for the water year to date for the Reno/Carson City area. The black line is showing the 2021–2022 water year with the percentage for the current water year annotated; the dashed blue line shows the mean; the dark blue shading shows the middle two-thirds of the years; and the cyan shows the range of all the years. Figure provided by D. Piece, CNAP and CW3E. View more locations and more information.

Total Precipitation: December 9–16

The images show total precipitation (inches) for the states of California and Nevada from 9-16 December 2021. Precipitation is shown from <1 inches (purple/blue) to >12 (gray). — Seven-day precipitation totals (inches) from the California Nevada River Forecast Center. Valid December 9–16, 2021.

Change in SWE and Snow Depth: December 12–16

Change in snow water equivalent (inches) for the states of California and Nevada from December 12-16, 2021

Change in snow depth (inches) for the states of California and Nevada from December 12-16, 2021. Snow depth is shown from <-100 (purple) to >100 (red). — Top: Five-day change in snow water equivalent (inches) for December 12–16. Bottom: Five-day change in snow depth (inches) for December 12–16. Source: California Nevada River Forecast Center.

California Reservoir Conditions

A map of California showing the location of 10 major reservoirs in California. Associated with each reservoir is a bar graph showing the total capacity, the historical average mark and the current capacity. Below the bar graph is the % of capacity (blue) and % of historical average (red line). Trinity Lake, Lake Shasta, San Luis Reservoir, Castaic Lake and Lake McClure are less than 50% of the historical average. — Reservoir levels and percent of historical average at 10 of the largest reservoirs in California as of December 15, 2021. Source: California Department of Water Resources.

Recent Drought Impacts

Find additional impacts through the National Drought Mitigation Center’s Drought Impact Reporter.
December 14: Governor of Nevada released a proclamation, "Climate Change Threatens Nevada with Aridification."
December 1: "The California Department of Water Resources Announces Initial State Water Project Allocation, Additional Actions to Prepare for Third Dry Year."
In early December, the California State Water Resources Control Board proposed new emergency drought regulations aimed at wasteful water practices. Comments are due by December 23.
November 9: The Metropolitan Water District declared a drought emergency.
October 19: The Governor of California expanded the drought emergency statewide.
Water Supply: The San Francisco Public Utilities Commission declared a water emergency and encouraged customers to curb water use by 10% compared to 2019–2020. Cities across California continue to amp up drought response and conservation efforts.
Agriculture: Almond production in California is expected to drop 10% because of high temperatures and drought. Drought has also led to lower yield and smaller citrus fruit.
Wildlife & Ecosystems:
- November 19:" California Department of Fish and Wildlife Saves More Than 2 Million Chinook Salmon From Drought; Begins Releasing Fish Into Klamath River As Conditions Improve."
- Migrating birds have been hit hard by California’s drought (CalMatters).
Recreation and Tourism:
- The slow start to the snow season is impacting snow recreation, including delaying the opening of ski resorts, which has far-reaching impacts on the local economies.
- Drought has impacted some bird populations, with reported impacts on hunting in Nevada.

Report Your Drought Impacts

Drought & Climate Outlook

El Niño–Southern Oscillation (ENSO)

NOAA’s ENSO alert system status is currently a La Niña Advisory. La Niña is favored to continue through the Northern Hemisphere winter 2021–22 (~95% chance) and transition to ENSO-neutral during the spring 2022 (~60% chance during April–June). For more information, please check out the NOAA ENSO blog.

Subseasonal to Seasonal Drought, Temperature, and Precipitation Outlooks

Forecasts for the next three months show drought persisting across southern California and Nevada as well as the Colorado River Basin, with the exception of drought remaining but improving in northern and central California. Historically, La Niña is associated with dry to normal conditions in the southern part of California and Nevada. The area of improvement is forecasted based on high climatological precipitation, the wet short- and medium-range outlooks, and recently improved incipient conditions. The January-February-March outlook from the National Weather Service’s Climate Prediction Center shows below-normal or equal chances of normal temperatures for the region.

The forecast models are suggesting there will be another storm next week impacting mostly California. The 7-day forecast precipitation totals range from less than half an inch to five inches, with the northern California coastal mountains and Sierra Nevada mountains forecasted to get the most precipitation.

Seasonal Drought Outlook: December 16, 2021–March 31, 2022

Climate Prediction Center seasonal drought outlook, showing the probability drought conditions persisting, improving, developing, or being removed across the U.S. from December 16, 2021 to March 31, 2022. — U.S. Seasonal Drought Outlook for December 16, 2021 to March 31, 2022, showing the likelihood that drought will develop, remain, improve, or be removed. Source: NOAA Climate Prediction Center.

Temperature and Precipitation Outlooks: January–March 2022

Climate Prediction Center 3-month temperature outlook, valid for January to March 2022. Odds favor below-normal temperatures for parts of northern California and Nevada, with equal chances elsewhere.

Climate Prediction Center 3-month precipitation outlook for January to March 2022. Odds favor below-normal precipitation in southern California and Nevada, with equal chances of below, near, and above normal conditions elsewhere. — January through March 2022 temperature outlook (*top*) and precipitation outlook (*bottom*), showing the probability (percent chance) of above-normal, below-normal, and near-normal conditions. Source: NOAA Climate Prediction Center. How do I interpret these graphics?

Likelihood and Timing of Atmospheric River Conditions

Two figures show the probability of atmospheric rivers by (left) forecast day (x-axis) (from December 15, 2021) and latitude (y-axis) and (right) longitude (x-axis) and latitude (y-axis). The left figure scale ranges from <0.25 (light blue) to >0.95 (dark purple) and shows near term potential for an AR impacting the PNW, a lull, and then potential for more ARs impacting the west in the coming weeks. — The CW3E Atmospheric River (AR) Landfall Tool displays the likelihood and timing of AR conditions (here IVT>250 kg/(ms)) from December 16, 2021 at each point on the map in a line along the West Coast of North America or inland derived from either the NCEP Global Ensemble Forecast System or the ECMWF Ensemble Prediction System.

Drought Early Warning Resources

California

Nevada

California-Nevada DEWS

Prepared By

Amanda Sheffield
California-Nevada DEWS Regional Drought Information Coordinator, NOAA/NIDIS, CIRES
Email: amanda.sheffield@noaa.gov

Julie Kalansky
Program Manager, California-Nevada Climate Applications Program (a NOAA RISA team)
Email: jkalansky@ucsd.edu

Special Thanks

This drought status update is issued in partnership between the National Oceanic and Atmospheric Administration (NOAA), the California-Nevada Applications Program, a NOAA RISA team, and the Western Regional Climate Center at the Desert Research Institute to communicate the current state of drought conditions in California-Nevada based on recent conditions and the upcoming forecast. NIDIS and its partners will issue future drought updates as conditions evolve.