Drought Status Update for California-Nevada

Heat Compounds Drought Impacts as Wildfire Season Starts.

Register here for the Western Drought Webinar, July 20 at 10 a.m. PDT. This webinar is in lieu of the July CA-NV Drought and Climate Outlook Webinar, which will return in September.

Key Points

After 2 water years of dry conditions, both California and Nevada are 100% in moderate-to-exceptional drought.
Reservoirs throughout California and Nevada are low, though the total reservoir storage is not as low as during the 2012–2016 drought.
Continued drying increases wildfire risk throughout the region, reflected in several recent large wildfire incidents in northern California.
Nevada and California had record warm temperatures in June, escalating drought-related impacts, including fire potential, water temperature impacts on fish, and increased evaporative demand.
Drought impacts (e.g., pasture conditions, ecosystem health, water supply, recreation, fire potential) have intensified and expanded given back-to-back dry years. Drought preparedness is key.

U.S. Drought Monitor Conditions: California-Nevada | July 6, 2021

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 July 6, 2021:

100% of California is experiencing Moderate (D1) to Exceptional (D4) Drought (52% in D3, 33% in D4)
California population in drought: 37,250,607
100% of Nevada is experiencing Moderate (D1) to Exceptional (D4) Drought (36% in D3, 41% in D4)
Nevada population in drought: 2,700,554

Source(s): NDMC, NOAA, USDA

U.S. Drought Monitor Categories

Last Updated: 07/06/21

100%

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

85.4%

of California is experiencing Extreme to Exceptional Drought (D3-D4)

76.9%

of Nevada is experiencing Extreme to Exceptional Drought (D3-D4)

Current Conditions

According to the U.S. Drought Monitor, over the last 4–8 weeks, drought conditions continued to worsen across all of California, including (most recently) the central coast. Both California and Nevada continue to be 100% in drought, with D4 (D3) present in California for 29 (63) weeks and Nevada for 42 (49) weeks.
Since October 2019, much of California and Nevada are missing 0.5 to 1+ years' worth of precipitation, and California 1.5+ years of missing streamflow. Streamflow is "missing" more than precipitation, illustrating the non-linearities between precipitation and streamflow.
The current drought is a combination of a precipitation deficit and a surplus of evaporative demand (the atmospheric conditions that drive evapotranspiration, leading to the drying of the landscape). Throughout southern Nevada and the Central Valley, evaporative demand has been a larger driver of the drought than the precipitation deficit.
Evaporative demand remains high as it has been throughout this water year, and vegetation is showing stress.
Record warm statewide temperatures for Nevada and California were set in June, punctuated by numerous daily maximum temperature records set during a series of heat waves.
Most of the 10 largest reservoirs in Northern California are at 5th–25th percentile levels for this time of year, with Lake Oroville near a record low. Almost all of Nevada reservoirs are below average capacity for this time of year.
Flows remain much below to extremely below normal, and high soil moisture deficits remain. For more detail, visit the California and Nevada Natural Resources Conservation Service Water Supply Outlooks.
The current drought conditions have led to concern for the wildfire season. As of July 8, six large incidents are occurring in Northern California.

How Is Drought Affecting Your Neighborhood?

Click to see drought indicators, outlooks, and historical conditions by city, county, and state, and to sign up for U.S. Drought Monitor alert emails.

Percent of Normal Precipitation: Last 30 Days and Water Year to Date

Percent of normal precipitation for California and Nevada over the past 30 days, through 7/5/2021. CA-NV has been extremely below normal precipitation continuing the trend since the start of the water year. The exception being parts of the central Sierra and southern Nevada over the past 30 days.

Percent of normal precipitation for California and Nevada for the Water Year to date, from October 1, 2020 to July 5, 2021. CA-NV has been extremely below normal precipitation continuing the trend since the start of the water year. — Percent of normal precipitation for the last 30 days (*top*) and since the start of water year (*bottom*) through July 5, 2021. Source: High Plains Regional Climate Center.

Statewide Mean Temperatures for June: 1895–2021

Statewide California temperatures for June for 1895-2021 using data from PRISM and the Westwide Drought Tracker. Notably, California had its warmest June temperatures in the instrumental record last month.

Statewide Nevada temperatures for June for 1895-2021 using data from PRISM and the Westwide Drought Tracker. Notably, Nevada had its warmest June temperatures in the instrumental record last month. — Statewide mean temperatures for June for California (*top*) and Nevada (*bottom*) during 1895–2021. Source: WestWide Drought Tracker.

Precipitation and Streamflow Deficits

Two maps of California and Nevada showing the missing or excess number of years of precipitation (left) and streamflow (right) as of June 1, 2021 based on normal (1981-2010 average) water year conditions. Northern California and Washoe County are missing over a year’s worth of precipitation. Coastal California is missing 1.25-1.75 years worth of stream flow. — The number of normal (average) water year's worth of precipitation (*left*) and streamflow (*right*) missing or in excess since the beginning of the most recent drought, October 2019. Streamflow missing is shown from U.S. Geological Survey stream gauges (*circles*) and California Department of Water Resources estimated natural flow (*stars*). Source: California-Nevada Climate Applications Program (CNAP) and Public Policy Institute of California (PPIC).

Contribution of Precipitation Deficit and Evaporative Demand Surplus

Three maps of California Nevada showing the precipitation deficit between October 2019–May 2021 (left panel), the surplus of evaporative demand between October 2019–May 2021 (middle panel), and the relative contribution of both drivers (right panel). he areas of highest precipitation deficits are the Sierra Mountains and much of coastal northern California. Much of the California Nevada region is showing an evaporative demand surplus between 0-250 mm with greater surplus in northern California. — Left: The precipitation deficit from October 2019 through May 2021. Middle: The surplus evaporative demand (ETo), or the atmospheric conditions leading to the drying of the landscape, from October 2019 to May 2021. Both precipitation deficits and ETo surpluses lead to drought. The relative contribution of these two drivers of drought is shown on the right. Red colors indicate drought dominated by precipitation deficits, and green colors indicate a drought dominated by ETo. White colors show the contribution of both drivers. Source: CNAP and PPIC.

Nevada Reservoir Conditions

A bar chart of Nevada reservoirs, showing the average capacity of each reservoir as a percent of the total capacity, alongside the current capacity for each reservoir. All reservoirs, except Mohave, are below average capacity. Lake Mead is missing data for the current capacity. — A current summary of reservoirs conditions in Nevada, as of July 1. The black outline indicates the average capacity as a percentage of total capacity at each reservoir. The blue shading is the current capacity. Note that Lake Mead is missing current capacity data in this figure. All reservoirs except Mohave are below average capacity. Figure courtesy of S. McAfee.

Water Storage + Snowpack in Western Sierra Reservoirs

Time series graphic showing water storage tracking (reservoirs + snow pack) in millions of acre-feet (Y-Axis) for Oct 1, 2020 thru Oct 1, 2021 (X-axis) for the 28 Western Sierra reservoirs. In the Western Sierra, reservoir normals are below normal with snowpack depleted. — CNAP Water Storage Tracking comparing current below-normal reservoir and snowpack in the Western Sierra Nevada to 1981–2010 normals through the beginning of July 2021.

Oroville Reservoir Water Storage

Time series from Oct 2019 through Oct 2021 showing water stored (thick blue line) in Oroville lake in millions of acre feet. Oroville Reservoir levels are near record low after dropping over the last year. — Oroville reservoir from the start of the 2020 Water Year (Oct. 1, 2019) through October 2021, compared to 1971–2020 reservoir storage percentiles. Source: CNAP 2020–2021 Drought Years Reservoir Tracker (visit to see similar graphics and more for 10 major Northern California reservoirs).

Precipitation Percentiles for Northern Coastal California: 1900–Present

Time series (horizontal axis) of precipitation percentiles from 1900 to present as a function of timescale (vertical axis) for California Climate Division 1 (northern coastal California) The timescale indicates the length of the averaging period. The dark red/orange colors denote periods of very low precipitation while the darker blue colors indicate periods of relatively wet conditions. The recent drought (2020-2021) shows an intensification of drought over the last 18-24 months. — Time series of precipitation percentiles (*horizontal axis*) from 1900 to present as a function of timescale (*vertical axis*) for California Climate Division 1 (northern coastal California). The timescale indicates the length of the averaging period. For instance, a timescale of 6 months is the average precipitation over the 6-month period ending (and including) the month noted on the horizontal axis. The dark red/orange colors denote periods of very low precipitation while the darker blue colors indicate periods of relatively wet conditions. The percentiles were calculated using NOAA climate division precipitation data extending from 1895 to present. More information, including other climate divisions, can be found here. Source: CNAP.

Soil Moisture Conditions

Vegetation Drought Response Index (VegDRI)

A CONUS map of the Vegetation Drought Index (VegDRI) for 7/4/2021. The color scale ranges from extreme drought (dark brown) to near normal (white) to extreme moist (green). Areas where the vegetation conditions are in moderate to extreme drought are found in all western states, the northern plains, and parts of the midwest and the northeast. — Vegetation Drought Response Index (VegDRI) conditions from July 4, 2021. VegDRI is a weekly depiction of drought's effects on vegetation stress across the contiguous United States. Source: National Drought Mitigation Center, U.S. Geological Survey, High Plains Regional Climate Center.

Recent Drought Impacts

Find additional impacts through the National Drought Mitigation Center's Drought Impact Reporter.
Condition Monitoring Observer Reports (CMOR) over the past month highlight impacts in crop production, livestock production, municipal water supplies, to households, recreation and tourism, wildlife habitat, and regarding fire.
In early June, Nevada Governor Sisolak signed legislation to enact permanent bans on certain categories of grass.
California has finished construction of a $10 million emergency rock barrier to block salt water from contaminating state and federal pumps.
On June 15, the California State Water Resources Control Board issued new regulations to stop diversions in the Russian River watershed and sent notices of water unavailability to ~4,300 rights holders in the Sacramento–San Joaquin Delta watershed.

Wildlife:

Severe drought has forced 500,000 juvenile steelhead to be moved from Nimbus hatchery to Mokelumne River hatchery due to forecasted warm water temperatures.
The Nevada Department of Wildlife is hauling ~55,000 fallows of water to "guzzlers" in S. Nevada mountain ranges to help the bighorn sheep population and other species.
Joshua Tree National Park closed the 49 Palms trail to give bighorn sheep full access to nearby water.
Point Reyes National Seashore provided supplemental water for Tule Elk.
Widespread drought is leading to a surge in wildlife sightings in urban areas, including bears in California and rattlesnakes in Nevada.

Agriculture:

In Sonoma County, livestock farmers are selling animals and thinning herds to cope with dry pastures and high feed prices. Farmers are struggling as water storage is drying quicker than in 2014–2016.
Fruit and nut orchards are needing more water than normal due to dry soils, including pumping more and increasing electric bills.
Marin County ranches are selling cattle, and animals are reportedly lighter in weight.
Cattle sales are up, such as one-fourth to one-third since March, in markets near Bakersfield.

Water Supply:

Santa Clara Valley Water District declared a drought emergency. In response, the San Jose Water Company is limiting lawn and landscaping irrigation.
Sonoma City Council declared a stage 2 water shortage on June 15, mandating water use reductions.
Marin Municipal Water District is taking steps toward constructing an emergency water pipeline.
Irrigation deliveries are one of the shortest seasons on record for Fresno Irrigation District.
Nevada Irrigation District enacted mandatory water use restrictions.
California hydropower is at its lowest levels in more than 5 years. The Edward Hyatt Power Plant at Lake Oroville could fall too low for further power production within months.

Lake Oroville: June 4, 2019 vs. June 9, 2021

Landsat 8 images of Lake Oroville on June 4, 2019 (left) and June 9, 2021 (right), showing a dramatic increase in drought conditions and lower water levels over the 2 year period, — Landsat 8 images of Lake Oroville comparing June 4, 2019 and June 9, 2021. Source: NASA.

Wildfire:

California has already experienced a significant increase in the number of wildfires and acres burned compared to last year (>4,000 wildfires and >70,000 acres burned). Source: CAL FIRE.
Nevada has had 40,000 acres burned as of July 7. Source: Great Basin Coordination Center.
Sierra-Pacific, which owns 1.7 million acres of timber lands in northern California, has closed public access to these lands for fire danger. Source: Mountain Democrat.
Enhanced fire restrictions are in place on all national forest land in the Lake Tahoe basin.
The U.S. Bureau of Land Management has issued a fire prevention order on all its lands in Nevada.

California Wildfire Statistics: 2020 vs. 2021 Year-to-Date

California wildfire statistics for 2021 (through July 4) compared to the same period in 2020. In 2021 so far, California has had 4,599 fires burn 73,511 acres, compared to 3,847 fires burning 31,111 acres over the same period in 2020. — California wildfire statistics for 2021 year-to-date compared to the same period in 2020. Source: CAL FIRE.

Report Your Drought Impacts

Drought and Climate Outlook

El Niño/Southern Oscillation (ENSO)

NOAA’s ENSO alert system status is currently La Niña Watch.

ENSO-neutral is favored through the Northern Hemisphere summer and into the fall (51% chance for the August–October season), with La Niña potentially emerging during the September–November season and lasting through the 2021–22 winter (66% chance during November–January). For more information, please check out the NOAA ENSO blog.

Seasonal Drought, Temperature, and Precipitation Outlooks

During the upcoming three months, little drought relief is anticipated across California and the Great Basin, where much of the region is in its dry season and abnormal warmth is favored to persist. The July-August-September outlook from the National Weather Service's Climate Prediction Center shows increased odds of above-normal temperatures across the West. Most of the region has equal chances of above/normal/below precipitation, including those areas impacted by the summer monsoon.

Seasonal Drought Outlook: June 17–September 30, 2021

Climate Prediction Center seasonal drought outlook, showing the probability drought conditions persisting, improving, or developing from July to September 2021. Existing drought in California and Nevada is likely to persist through September. — U.S. Seasonal Drought Outlook for June 17 to September 30, 2021, showing the likelihood that drought will develop, remain, or improve. Source: NOAA Climate Prediction Center.

Three-Month Temperature and Precipitation Outlooks

Climate Prediction Center 3-month temperature outlook, valid for July to September 2021. Odds favor above-normal temperatures across California and Nevada during this period.

Climate Prediction Center 3-month precipitation outlook, valid for July to September 2021. Odds slightly favor below-normal precipitation across the northern borders of California and Nevada, with equal chances of above, below, and near-normal conditions in the rest of the region. — July through September 2021 temperature outlook (*top*) and precipitation outlook (*bottom*). A = chances of above-normal; EC = equal chances of above, below, normal; B = chances of below-normal. Source: NOAA Climate Prediction Center. How do I interpret these graphics?

Significant Wildland Fire Potential Outlook

According to the National Interagency Fire Center’s Predictive Services, fire activity increased significantly across the West during June. The national preparedness level increased to four on June 22, the second earliest occurrence since 1990.

The first surge of monsoonal moisture arrived in the Southwest, including the southern Great Basin, during the last few days of June. Near-normal precipitation is likely with the Southwest monsoon in July. Above-normal significant fire potential will expand northward into the Great Basin through August with areas closer to the monsoon likely returning to near normal.

In northern California, the low elevation grass crop is cured below 3,000 feet, and fuel loading among low-elevation brush and grasses is near to below average due to a second year of drought. The high-elevation snowpack has melted off, and although dead fuels are quite dry, live fuels still retain some moisture and greenness as June ends. Similar to May, in southern California both the 1,000-hour and 100-hour dead fuel moistures are below the third percentile and broke many record low values away from the coastal areas in June. The live fuel moisture continues to slowly dry out and is around a month and a half ahead of where it should be for this time of year. Corresponding current fire danger realized through the Energy Release Component is above normal for much of California and Nevada.

Most of the mountains and foothills in California are forecast to have above-normal significant fire potential through September. Much of central and southern California will have above-normal significant fire potential from July to September due to the expected above-normal temperatures and the very dry fuel conditions. Above-normal significant fire potential will continue across southern California from the mountains westward in October as very dry conditions are expected to continue along with the start of the Santa Ana wind season.

Energy Release Component Anomaly

California-Nevada map showing Energy Release Component departure from 1991-2020 average for 7/6/2021. Areas of above normal Energy Release Component highlight areas of enhanced large fire potential where fuels are available. — Energy Release Component departure as of July 6, 2021 relative to 1991–2020 normal. Source: Climate Toolbox.

Significant Wildland Fire Potential Outlook: July–September 2021

Significant Wildland Fire Potential Outlook for July 2021, which shows above normal fire potential along the California coast, parts of northeast to east-central California, and parts of eastern Nevada.

Significant Wildland Fire Potential Outlook for September 2021, which shows above normal fire potential along the California coast, northern California, and into parts of central California. — Significant Wildland Potential Outlook for July (*top*), August (*middle*) and September (*bottom*) 2021 from NIFC Predictive Services. Above-normal indicates a greater than usual likelihood of significant fires.

Drought Early Warning Resources

California Nevada California-Nevada DEWS

Prepared By

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

Julie Kalansky
Program Manager, California-Nevada Applications Program (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.