California-Nevada Drought Status Update

Water Year 2023 Recap: An Extreme Drought Buster

Key Points

According to the U.S. Drought Monitor, the California-Nevada Drought Early Warning System region began Water Year 2023 100% in drought and ended with less than 1% of the region in drought.
Cool, wet conditions throughout the year led to a record snowpack in the Southern Sierra Nevada and the reemergence of Tulare Lake.
Responsive actions to the wet conditions included a California executive order to maximize the opportunity for groundwater recharge.
El Niño is here and expected to persist and peak in winter, although outlooks currently suggest equal chances of above-, below-, and near-normal conditions. This is in contrast to the traditional El Niño precipitation pattern of a normal to wet southern portion of the California-Nevada region.

U.S. Drought Monitor Conditions | October 17, 2023

U.S. Drought Monitor

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 October 17, 2023:

5.68% of California is experiencing Abnormally Dry (D0) conditions
1.6% of Nevada is experiencing Moderate (D1) drought
4.12% of Nevada is experiencing Abnormally Dry (D0) conditions

Source(s): NDMC, NOAA, USDA

U.S. Drought Monitor Categories

Last Updated: 10/19/23

0.66%

of California-Nevada is in drought

2.89%

of California-Nevada is Abnormally Dry (D0)

Current Conditions

According to the U.S. Drought Monitor, less than 1% of California-Nevada remains in drought, compared to 100% a year ago. This means a 5-drought class improvement in areas such as the Central Valley.
Wetter than normal conditions—greater than 150% of normal for many areas—brought the end of the 4th multi-year drought period in the last two decades.
Over Water Year 2023, California experienced 31 atmospheric rivers (ARs) (many penetrating into Nevada), based on CW3E analysis. Cumulatively, precipitation reduced or eliminated precipitation deficits that have been building since Water Year 2020.
Most recently, parts of southeastern California and adjacent Nevada and Utah saw drought removal/improvement due to heavy rainfall from Hurricane Hilary and its remnants.
Water Year 2023 was also one of the coolest in the last 40 years, resulting in more precipitation falling as snow instead of rain in the Sierra Nevada and much of Nevada, even compared to other wet years like 1983 and 2017. The cool spring resulted in a slow spring melt of the massive snowpack that accumulated in January and March.
Reservoirs throughout the region are at or above historical averages going into Water Year 2024.
The Colorado River Basin experienced a wet year as well, with Lake Powell plus upstream reservoirs increasing by about 5 million acre-feet (maf) during Water Year 2023. Based on the current forecast of 9.40 maf unregulated inflow for Water Year 2024, the October 24-Month Study projects Lake Powell elevation will end calendar year 2024 near 3582.86 feet with approximately 9.52 maf in storage (41% of capacity)
Thus far this fire season, fire activity has been relatively low with the exception of northwest California in August, requiring extra resources in the region.
For more information, check out Living with Drought in Nevada and the California Water Year 2023 Brochure.

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U.S. Drought Monitor 52-Week Change Map

From October 18, 2022 to October 17, 2023, California and Nevada saw 1- to 5-category drought improvements on the U.S. Drought Monitor. — U.S. Drought Monitor 52-week change map, showing where drought has improved, degraded, or remained the same from October 18, 2022 to October 17, 2023. Source: National Drought Mitigation Center.

Historical U.S. Drought Monitor Conditions for California-Nevada

Wetter than normal conditions this year brought the end of the 4th multi-year drought period in the last two decades for California-Nevada. — Timeseries showing historical drought conditions for the California-Nevada region from 2000 to the present, according to the U.S. Drought Monitor. The U.S. Drought Monitor is a joint product of NOAA, USDA, and the National Drought Mitigation Center. Image courtesy of the Drought.gov Historical Data & Conditions Tool.

Percent of Normal Precipitation: Water Year 2023

During Water Year 2023, precipitation totals were greater than 150% of normal for much of the region. — Percent of normal precipitation for Water Year 2023 (October 1, 2022–September 30, 2023). Source: High Plains Regional Climate Center.

Departure from Normal Temperature: Water Year 2023

tbd — Departure from normal temperatures for Water Year 2023 (October 1, 2022–September 30, 2023). Source: High Plains Regional Climate Center.

Atmospheric River Landfall Events

tbd — California had 32 atmospheric rivers in Water Year 2023. Figure provided by C. Hecht at CW3E. A full summary of atmospheric rivers events during Water Year 2023 will be available soon at cw3e.ucsd.edu.

California-Nevada Precipitation Anomalies Since October 1, 2019

The central and coastal southern California deficits were from <0.5 years to >1 years at the start of the water year. By the start of the Water Year 2023 , those deficits had been reduced to no remaining deficit. — California-Nevada accumulated precipitation deficits from October 2019 (left) through October 1, 2022 (start of Water Year 2022) and (right) through October 1, 2023 (start of Water Year 2023) shown in normal water year's worth of precipitation. Figure provided by M. Dettinger, CNAP.

Percentage of California with Lowest Precipitation Deficits Since October 2019

Time series from September 2022 through September 2023 showing the percent of California area without a precipitation deficit (solid line), less than half a year of deficit (dashed line), and less than 1 year of deficit (dotted line) that began accumulated as of October 1, 2019. The three largest steps occur in January 2023, March 2023, and August 2023 (due to Hurricane Hilary). — A monthly time series from September 2022–September 2023 showing the percent of area in California without a precipitation deficit (solid line), less than 0.5 year of deficit (dashed line), or less than 1 year of deficit (dotted line). The deficit is as of October 1, 2019. Figures provided by M. Dettinger, CNAP.

Fraction of Precipitation That Fell as Snow: October–April 1983, 2017, 2023

tbd — Maps of California and Nevada showing the fraction of precipitation that fell as snow between October and April based on days with precipitation and temperature average below 0°C (32°F) for three very wet years (1983, 2017, 2023). Figure provided by M. Dettinger, CNAP.

Evaporative Demand Rankings for the Last 4 Water Years

Much of California has record setting evaporative demand and Western Nevada had 5th in water year 2021. In water year 2022 much of the region was in the mid range of the historical period with the exception of the Central Coast and southeast of California which was higher. In WY 2023, much of the California Nevada region had evaporative demand ranks in the lowest 10 years in the 43 year history. — Maps showing how the last four Water Years compare in evaporative demand (the atmospheric “thirst”) by rank since 1980. Black indicates that 2021 had the highest evaporative demand while 2023 evaporative demand was near the lowest ranks for parts of the region. Figure provided by M. Dettinger, CNAP.

Water Storage in the Sierra and Tulare Basin

All the Sierra region had well above reservoir plus snowpack totals in April and May, with the largest anomalies in the Southern Sierra.

In the Tulare basin, the reservoir+snowpack peak in April is 3 times normal and reservoirs are near normal. Near July the snowpack melted and reservoir level was at the combined total. — Water storage, a combination of snowpack and reservoir storage, as of September 30, 2023 (end of Water Year 2023) compared to normal for the three regions in the Sierras and Tulare Basin. Note the difference in normal periods: 2000–2015 for the Sierra Regions and 2003–2020 for the Tulare Basin. Provided by M. Dettinger. Additional regions are available from CNAP Water Storage Tracking.

California Major Water Supply Reservoirs

A map of California showing the location of 17 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) as of October 1, 2023. All the reservoirs are above the historical averages except for Lake Trinity. — Reservoir levels and percent of historical average at 10 of the largest reservoirs in California as of October 1, 2023. Source: California Department of Water Resources.

Nevada Reservoir Levels

A bar chart with the names of Nevada reservoirs on the left as of October 1, 2023. The black outline of a bar shows the average capacity of each reservoir as a percent of the total capacity. Blue shading represents the current capacity of the reservoir. Most reservoirs are showing above average capacity except for Lake Mead, Marlette Lake. — A current summary as of October 1, 2023 of Nevada reservoir levels. The black outline indicates the average capacity as a percentage of total at each reservoir. The blue shading is the current capacity. Figure courtesy of K. Rhodes, Nevada State Climatologist Office, data from Natural Resources Conservation Service.

Water Year 2023 Drought Impact Summary

At the start of Water Year 2023, drought continued to impact California and Nevada water supply, agriculture, ecosystems and more. Extremely wet conditions, in part due to 32 atmospheric rivers, shifted the region’s focus from drought concerns to flooding within months. Actions included California Governor Newsom issuing an Executive Orders enabling more recharge of flood water to test a drought adaptation strategy. In the Colorado River System, the Inflation Reduction Act and Bipartisan Infrastructure Law together include $15.4 billion to enhance the West’s resilience to drought.

However, long-term drought impacts remain. For example, there are limits to groundwater recovery despite a wet year. According to the California Natural Resources Agency semi-annual groundwater conditions update, “It will likely require several more wet years and more focused efforts to increase recharge and reduce pumping to recover from the most recent drought and the cumulative depletion of groundwater aquifers that has occurred over decades.” Managing water and farmland transitions in the San Joaquin Valley with Sustainable Groundwater Management Act will also be key (Public Policy Institute of California). The California Department of Water Resources also awarded $187 million to 32 groundwater subbasins through the Sustainable Groundwater Management Grant Program in September.

California Groundwater Level Change: Spring 2022–Spring 2023

A map of California with water basins shows one year groundwater level changes from Spring 2022 to Spring 2023. The scale ranges from decreases greater than 25 feet (red) to increases greater than 25 feet (blue). Many observations showed an increase to no significant change (yellow) with decreases most present in the Tulare Lake basin. — Statewide and hydrologic region groundwater level change map for one-year period between spring 2022 and 2023. Source: California’s Groundwater Conditions, Semi-Annual Update: October 2023

Recent and Potential Drought Impacts

Find additional impacts through the National Drought Mitigation Center’s Drought Impact Reporter.

Report Your Drought Impacts

Drought & Climate Outlook

El Niño–Southern Oscillation (ENSO)

NOAA’s ENSO alert system status is currently an El Niño Advisory. El Niño is anticipated to continue through the Northern Hemisphere spring (with an 80% chance during March–May 2024). At its peak (November–January), nearly all models suggest a moderate-to-strong El Niño. For more information, check out the NOAA ENSO blog and current status presentation. Note, not all El Niños elicit the same response in California and Nevada and can vary. Explore this more for your region of interest with the newly updated Western Regional Climate Center ENSO Precipitation tool.

Past ENSO Conditions vs. October–March Precipitation

Two figures show past ENSO conditions (according to Nino 3.4) (X axis) versus October-March precipitation (inches) (Y axis) for the California San Joaquin drainage (top) and Nevada extreme southern region (bottom). El Nino conditions are indicated in red, neutral ENSO conditions in green, and La Nina conditions in blue. In the San Joaquin drainage basin, precipitation outcomes are spread for all three ENSO categories while in extreme southern Nevada, La Nina tends toward dry but is more spread in the other ENSO categories. — Past ENSO conditions (according to Nino 3.4) versus October-March precipitation (inches) for the California San Joaquin drainage (top) and Nevada extreme southern region (bottom). El Nino conditions are indicated in red, neutral ENSO conditions in green, and La Nina conditions in blue. Source: Western Regional Climate Center.

Subseasonal to Seasonal Drought, Temperature, Precipitation, and Fire Outlooks

The autumn and early winter months are a highly transitional time of year, as the wet season begins to ramp up along the West Coast. Current conditions have led to a normal or below-normal fire potential outlook for California-Nevada. Despite current ENSO conditions, it remains to be seen if we can expect canonical El Niño impacts in the U.S., including in California and Nevada.

Short term forecasts (<2 weeks) show the potential for a cooler, wetter period for California and Nevada. However, over the next 3 months, the National Weather Service’s Climate Prediction Center seasonal forecast leans towards warmer than normal conditions with an equal chance of above-normal, normal, or below-normal precipitation. Given this, the seasonal drought outlook primarily shows no drought development for the region and drought persistence in the small area of remaining drought in southern Nevada.

Seasonal Drought Outlook: October 19–January 31

Over the next 3 months, the National Weather Service’s Climate Prediction Center seasonal forecast leans towards warmer than normal conditions with an equal chance of above-normal, normal, or below-normal precipitation. Given this, the seasonal drought outlook primarily shows no drought development for the region and drought persistence in the small area of remaining drought in southern Nevada. — U.S. Seasonal Drought Outlook. Valid for October 19, 2023–January 31, 2024. Source: NOAA NWS Climate Prediction Center. Map courtesy of Drought.gov.

Seasonal (3-Month) Outlooks Temperature and Precipitation Outlooks

For October 19, 2023 through January 31, 2024, there are equal chances of above or below normal precipitation across California and Nevada.

Drought Early Warning Resources

California

Nevada

California-Nevada DEWS

Prepared By

Amanda Sheffield
NOAA/NIDIS California-Nevada DEWS Regional Drought Information Coordinator, Cooperative Institute for Research in Environmental Sciences (CIRES)

Julie Kalansky
Program Manager, California-Nevada Adaptation Program (A NOAA CAP/RISA team)

Special Thanks

This drought status update is issued in partnership between the National Oceanic and Atmospheric Administration (NOAA), the California-Nevada Adaptation Program (a NOAA CAP/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 status updates as conditions evolve.