California-Nevada Drought Status Update

Extremely Wet and Cool Winter Alleviates Most of the Region’s Drought

Key Points

According to the April 18, 2023 U.S. Drought Monitor, 14.6% (only ~1% Severe Drought) of California-Nevada remains in drought, with no Extreme or Exceptional Drought. Drought has not been this low in California-Nevada since late February 2020.
Snowpack is still above 200% of normal for this time of year as a result of a wet, cold winter and early spring. Concerns have turned towards flooding in the Central Valley from the record precipitation and snowmelt.
An El Niño Watch has been issued favoring a start this summer and continuing into winter, with 62% confidence despite typically less accurate spring forecasts.

U.S. Drought Monitor Conditions | April 18, 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 April 18, 2023:

8.79% of California is experiencing Moderate (D1) to Exceptional (D4) Drought (0% in D3, 0% in D4)
California population in drought: 743,141
22.93% of Nevada is experiencing Moderate (D1) to Exceptional (D4) Drought (0% in D3, 0% in D4)
Nevada population in drought: 1,814,717

Source(s): NDMC, NOAA, USDA

U.S. Drought Monitor Categories

Last Updated: 04/18/23

14.6%

of California and Nevada are in drought

of the region is in extreme (D3) or exceptional (D4) drought

Atmospheric Rivers hit CA in Water Year 2023

Current Conditions

According to the U.S. Drought Monitor, there is no extreme (D3) or exceptional drought (D4) in California-Nevada, and only 1.14% of the region, in Clark County, is in severe drought (D2). California has not seen D1/D0 only conditions since March 2020.
California has experienced 31 atmospheric rivers (ARs) in Water Year (WY) 2023 through March, based on CW3E analysis, which have delivered between 1.5 to 2 water years' worth of precipitation in much of the state. These ARs have penetrated into Nevada, providing normal or much above normal precipitation for the northern two-thirds of the state.
The region has been extremely cool this WY, and in particular, much of the region in the last three months experienced temperatures 3–9 degrees below normal. This has helped to maintain the snowpack.
Snowpack remains well above normal for this time of year—over 200% of normal in many parts of the region. Snowmelt is now underway as seen in satellite imagery.
The precipitation from December to March has alleviated much of the precipitation deficit in the California central and south coast region.
The accumulated runoff for the San Joaquin Basin is still forecasted to be below the mean over the WY 2020–2023.
Storage levels in many of California reservoirs are near the historical average for this time of year with Oroville and Shasta, the state’s two largest reservoirs, above the average. Lake Shasta has reached water levels not seen since 2019, which benefits hydropower generation.
Given this winter’s severe winter storms, on April 3 President Biden on April 3 approved a California Disaster Declaration, making funding available to affected individuals in Kern, Mariposa, Monterey, San Benito, Sata Cruz, Tulare, and Tuolumne counties.
In Nevada, reservoirs are at 35% of capacity, which is 77% of the median. Lake Tahoe is above the rim and at 39% of capacity, which is 100% of the median capacity for this time of year.
In the Upper Colorado, the combined snowpack and storage of the 20 upstream reservoirs of Lake Powell is above normal for this time of year. The U.S. Bureau of Reclamation had released a draft Supplemental Environmental Impact Statement for Near-term Colorado River Operations with public comment open for 45 days.
Long-term drought impacts remain. Dry wells continue to be reported in the Central Valley. Groundwater may not have fully recovered from the 2012–2016 drought before the start of the most recent drought, and the ability to recharge is yet to be seen. Recently, a west coast ban on salmon fishing was approved in part due to long-term drought. On April 13, The U.S. Bureau of Reclamation announced the 2023 Klamath Project water supply allocations, as well as a $13 million for drought resiliency, ecosystem enhancement, and groundwater monitoring in the Klamath Basin.
For more information, check out Living with Drought in Nevada and the California Water Watch.

How is drought affecting your neighborhood? Click to see drought indicators, outlooks, and historical conditions by city, county, and state, as well as sign up for alerts.

View local drought information

U.S. Drought Monitor Water Year 2023 Change Map

From October 1, 2022 to April 18, 2023, all of California and Nevada has seen drought improvements, with parts of California seeing 4- to 5-category improvements, according to the U.S. Drought Monitor. — U.S. Drought Monitor change map since the start of Water Year 2023, showing where drought has improved, degraded, or remained the same from October 1, 2022 to April 18, 2023. Source: National Drought Mitigation Center.

Percent of Normal Precipitation: Water Year and Last 60 Days

Since the start of Water Year 2023, precipitation is over 100% of normal for most of California and Nevada, except for the lower southeast corner of the region.

Over the last 60 days, much of the southern and central part of California and eastern Nevada is above 150% of normal precipitation. The Southeast part of the region is between 5% to 90% of normal. — Top: Percent of normal precipitation since the start of Water Year 2023 (October 1–April 18). Bottom: Percent of normal precipitation for the past 60 days (February 18–April 18). Source: High Plains Regional Climate Center.

Departure from Normal Temperature: Water Year and Last 60 Days

Since the start of the water year, much of the region is 0 to 4 degrees cooler than normal, with some regions in northeastern Nevada and along the California Nevada border ranging from 4 to over 10+ degrees below normal.

From February 18 to April 18, most of the region has experienced near to below normal temperatures, with the biggest departures from normal in northern Nevada and along the California-Nevada border. — Top: Departure from normal temperature since the start of Water Year 2023 (October 1–April 18). Bottom: Departure from normal temperature for the past 60 days (February 18–April 18). Source: High Plains Regional Climate Center.

Snow Water Equivalent (SWE)

Accumulated Precipitation and Streamflow: December 2022–March 2023

The entire California Nevada region, except the southeast corner of the region, has received 100% of normal precipitation and much of the central region receiving over 200% of normal. Annual streamflow generally matches the precipitation except for areas along the central coast having higher annual stream flows than precipitation relative to normal. Some of the highest annual stream flows have been along the central coast. — The accumulated precipitation over California-Nevada from December 2022–March 2023 as a percentage of the 1981–2010 normal. The contours show 100% (*dashed*) and 200% (*solid*) of normal precipitation. The colored circles show the percent of normal natural streamflow for the same period, and the size of the crosses indicates the 2023 peak streamflow relative to the 1981–2010 normal. Figure provided by M. Dettinger.

Accumulated Precipitation Deficits for California-Nevada

For October 2019 to November 2022, the central and coastal southern California precipitation deficits were between <0.5 water year's to >1 water year's worth of precipitation. By the end of March 2023, those deficits had been reduced to no remaining deficit. Thus the precipitation deficits over the past three years were undone in this region. — Map of California-Nevada accumulated precipitation deficits from (*top left*) October 2019 through November 2022 and (*top right*) October 2019 through March 2023 shown in normal water years' worth of precipitation. The bottom map shows the accumulated precipitation difference between the top two maps—the precipitation deficits from December 2022–March 2023. Figures provided by M. Dettinger.

Snow Water Equivalent in Nevada and the Eastern Sierra

Current snow water equivalent for Nevada and the Eastern Sierra is 263% of median. — Snow water equivalent (inches) for the state of Nevada and the Eastern Sierra. The graph shows the current water year (*black line*) alongside the median (*green line*), minimum (*red line)*, and maximum (*purple line*). Source: USDA Natural Resources Conservation Service.

Central Valley Water Resources Index: Streamflow

A time series of Central Valley Water Resources Index (a proxy for streamflow volume available all along the Sierra in the Central Valley) daily observed volumes (right axis and shown in grey) and multi year volume accumulation from October 1, 2019 to April 11, 2023 as well as forecasted through the end of water year 2023. The observed peak occurred on March 15, 2023. The 4 year accumulated volume is projected to be about 75% of the median. — A time series of Central Valley Water Resources Index (a proxy for streamflow volume available all along the Sierra in the Central Valley) daily observed volumes (*grey*) and multi-year volume accumulation (*pink*) in thousands of acre-feet from October 1, 2019 (start of Water Year 2020) to April 11, 2022, as well as forecasted near-record 3-year low through the end of Water Year 2023 (September 30, 2023). The observed peak occurred on March 15, 2023. Source: NOAA NWS California-Nevada River Forecast Center.

Water Storage + Snowpack in the Tulare Basin

The reservoir+snowpack are about 3 times normal and reservoirs are near normal. Snowpack plus reservoir is above both 1969 and 1983. — Water storage (a combination of snowpack and reservoir) as of 4/17/2023 compared to the 2003–2020 normal for the Tulare Basin. Provided by M. Dettinger. Additional regions available via CNAP Water Storage Tracking.

Nevada Reservoir Storage

As of April 1, most Nevada reservoirs are showing near-normal capacity except for Lake Mead, Rye Patch and Bridgeport. — A current summary of Nevada reservoir levels, as of April 1, 2023. 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 S. McAfee, Nevada State Climatologist, with data from Natural Resources Conservation Service.

Upper Colorado River Basin Water Storage

The Upper Colorado reservoir and reservoir + snowpack are about 7 million acre-feet above normal. — Water storage for the Upper Colorado, a combination of snowpack and 20 upstream reservoirs, compared to 1989–2018 normal as of April 12, 2023. Green lines show current (*thick line*) and normal (*thin line*) Lake Powell plus 20 upstream reservoir storage. Red lines show current storage for 20 upstream reservoirs (*thick line*) and reservoirs + snowpack (*thin line*). Source: CNAP Water Storage Tracking.

Drought & Climate Outlook

El Niño–Southern Oscillation (ENSO)

NOAA’s ENSO alert system status is currently an El Niño Watch. ENSO-neutral conditions are forecasted to continue during the spring. In May–July 2023, there is a 62% chance of El Niño conditions developing. For more information, check out the NOAA ENSO blog or current status presentation.

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

The May temperature and precipitation outlooks from the National Weather Service's Climate Prediction Center predict that California-Nevada will have primarily below-normal temperatures and equal chances of above-normal, normal, and below-normal precipitation. Subsequently, the seasonal forecast (May-June-July) shows equal chances in both temperature and precipitation. Given this, the next three-month drought outlook shows remaining drought persisting. Current fire outlooks from the National Interagency Fire Center (NIFC), given current and forecasted conditions, show normal to below-normal fire potential in California-Nevada through July.

Drought Outlook for April 20–July 31

From April 20 to July 31, existing areas of drought in California and Nevada are projected to persist. — U.S. seasonal drought outlook, showing where drought is forecasted to persist, improve, be removed, or develop from April 20 to July 31, 2023. Source: NOAA's Climate Prediction Center.

May 2023 Temperature and Precipitation Outlooks

In May 2023, odds favor below-normal temperatures in all but northern California, as well as in southwestern 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.