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Regional Drought Update Date
April 15, 2021
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Drought Status Update

Drought Status Update for California-Nevada


DEWS Regions:
States:
Update Status:

NIDIS and its partners will issue future drought updates as conditions evolve.

Region Transitions from Dry Winter to Dry Spring with Dry Soils, Rapid Snowmelt, and Intensified and Expanded Drought Impacts.

Key Points

  • After two water years of dry conditions, ~96% of California and Nevada is in moderate-to-exceptional drought. As of March, the last 18 months have been the second driest on record for both states. 
  • Abnormally dry conditions this winter were driven by a lack of landfalling atmospheric rivers and persistent ridging/blocking over the Northeast Pacific Ocean. 
  • Precipitation totals remain well below normal, and below-normal snowpack is melting rapidly. Dry soils are expected to reduce runoff, and vegetation is showing stress.
  • A warmer than normal summer is forecasted. Though many areas are currently showing record or near record fuel dryness, significant fire potential for many areas in California is expected to become above normal starting in July and continuing through the summer. Above-normal significant fire potential is expected in some mid to higher elevation areas in far southern Nevada by late May.
  • 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.
Current Conditions
U.S. Drought Monitor Conditions: California-Nevada | April 13, 2021

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 13, 2021:

  • 94% of California is experiencing Moderate (D1) to Exceptional (D4) Drought (33% in D3, 5% in D4)
  • California population in drought: 34,058,693
  • 100% of Nevada is experiencing Moderate (D1) to Exceptional (D4) Drought (34% in D3, 40% in D4)
  • Nevada population in drought: 2,700,553

U.S. Drought Monitor Categories

The color with the hex code #ffff00 identifies:
D0
The color with the hex code #ffcc99 identifies:
D1
The color with the hex code #f5ad3d identifies:
D2
The color with the hex code #ff0000 identifies:
D3
The color with the hex code #660000 identifies:
D4
Main Stats
94%
of California is experiencing Moderate to Exceptional Drought (D1-D4)
100%
of Nevada is experiencing Moderate to Exceptional Drought (D1-D4)
40%
of Nevada is experiencing Exceptional Drought (D4)

Current Conditions

  • According to the U.S. Drought Monitor, drought conditions degraded in pockets of California, including central and coastal California. Nevada remains 100% in drought and currently has more area in exceptional drought (D4) than at any point during the 2012–2016 drought.
  • With the exception of eastern Nevada, the last month was abnormally dry for the region with less than 25%–70% of normal precipitation. 
  • According to NOAA's National Centers for Environmental Information, California experienced its third driest year on record, and second driest 18 months. Nevada had its driest year on record, and the second driest in 18 months. The historical odds of reaching normal precipitation this water year are 10% or less in many places throughout California and Nevada. 
  • According to CW3E, abnormally dry conditions this winter were driven by a lack of landfalling atmospheric rivers and persistent ridging/blocking over the Northeast Pacific Ocean (read more here). 
  • On April 1, the California Department of Water Resources reported statewide snowpack at 59% of average for the date. Comparing 2021 to 2014, year-to-date precipitation totals have been similar. However, the snowpack is much different across elevations. This year’s snowpack was much heavier at the lower elevations due to the colder storms that have impacted the state. 
  • The low-elevation snowpack has contributed to the rapid snow melt. Since April 1, statewide snow survey measurements show rapid snow melt with snowpack now 40% of average, and most flows remain below to extremely below normal. High soil moisture deficits are expected to reduce runoff efficiencies. 
  • Storage in the largest northern California reservoirs is well below average and in Nevada is lower than it was this time last year, reflecting cumulative impacts from a dry 2020. For more detail, visit the California and Nevada Natural Resources Conservation Service Water Supply Outlooks. 
  • Evaporative demand (the atmospheric thirst that drives evapotranspiration) remains high as it has been throughout this water year, and vegetation is showing stress.
  • Across many areas of California, several indicators related to fire danger fuel dryness are currently at record or near record values. These reflect medium- to shorter-term weather and will change should cooler and wetter conditions occur over the next month or two. Otherwise, this is an early indication of potential significant fire this summer. Above-normal significant fire potential is expected in some mid to higher elevation areas in far southern Nevada by late May.
  • Given current conditions, three NOAA National Weather Service Weather Forecast Offices in the region have released drought information statements. You can read them here.  

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 vs. Water Year to Date

Percent of normal precipitation for California and Nevada through April 12, 2021.   For the past 30 days (left image), CA-NV has been extremely below normal precipitation/

Percent of normal precipitation for California and Nevada through April 12, 2021. Since the start of the Water Year on October 1, 2020, CA-NV has seen extremely below normal precipitation.
Percent of normal precipitation for the last 30 days (left) and since the start of water year (right). Valid through April 12, 2021. Source: High Plains Regional Climate Center.

Atmospheric River Landfalls

An end of winter meteorological story from CW3, which includes 2 tables and a map of the western U.S. The top left table shows the number of atmospheric rivers (ARs) impacting the west coast (most were weak to moderate) and the bottom left table shows the AR counts by region.  WA and OR were impacted by the most ARs, with some in N. CA. Only 1 moderate AR occurred on Jan 28th that impacted most of CA.
CW3E’s Atmospheric River (AR) Landfall map shows that only one AR made landfall in Central/Southern California. In Northern California, the ARs were only weak to moderate strength. The lack of ARs led to the drought this year. Read more from the CW3E’s winter summary here

Odds of WY 2021 Reaching Water Year Normal Precipitation for the West

 Three maps of the western United States show the odds of reaching 50%, 75%, and 100% of water year normal precipitation as of April 1, 2021 based on the historical record. Most of the west has a <20% chance of 100% normal, except for parts of the PNW including Montana. Most of California, southern NV, and western UT/AZ, have <40% chance of 75% of normal. Most of the West has a 100% chance of reaching 50% of normal precipitation except an area around San Francisco and Southern California and Nevada.
Odds of reaching 50% (top left), 75% (top right), and 100% (bottom) of normal water year precipitation as of April 1, 2021 throughout the West. Source: CW3E.

Snow Water Equivalent Percent of Median: April 12, 2021

A map of the western U.S. showing the percent of 1981-2020 median snow water equivalent values from the NRCS from 4/12/2021. SWE in the Sierras is primarily between <50% and 70%.
Snow water equivalent (SWE) percent of 1981-2010 median as of April 12, 2021. For an interactive version of this map, please visit the Natural Resources Conservation Service.

California Snow Water Equivalent: March/April 2014 vs. March/April 2021

Four scatterplots of north (blue triangles) and southern (red triangles) SIerra snow course data by elevation vs percent of normal April 1 SWE from March 2014, April 2014, March 2021, April 2021. Both water years 2014 and 2021 had similar amounts of precipitation, but the storms in 2021 were much colder storms producing more snow and at lower elevations. This is shown by the high SWE percentage at low elevations in the top right panel. The decrease in SWE at the lower elevation by April in 2021 shown in the bottom right panel is a result of snow melting rapidly at these elevations.
The figure shows the difference in snow water equivalent (SWE) for California snow course data. The left two panels show 2014 the percent of April 1 SWE by elevation for 201, and the right two panels show the same for 2021. The top two panels use the snow course data from March of the respective years, and the bottom two panels from April.  Both water years had similar amounts of precipitation, but the storms in 2021 were much colder, producing more snow and at lower elevations. This is shown by the high SWE percentage at low elevations in the top right panel. The decrease in SWE at the lower elevation by April in 2021 shown in the bottom right panel is a result of snow melting rapidly at these elevations.  Figure courtesy of Mike Dettinger, California-Nevada Climate Applications Program (CNAP).

Water Storage in the Western Sierra Nevada 

Time series graphic showing water storage tracking (reservoirs + snow pack) in millions of acre-feet for Oct 1, 2020 through Oct 1, 2021 for the 28 Western Sierra reservoirs.  In the Western Sierra, reservoir normals are below normal and reservoir+snowpack are well below normal and indicating rapid melt off with less of an increase in reservoir storage.
CNAP Water Storage Tracking comparing current below-normal reservoir and snowpack in the Western Sierra Nevada to 1981-2010 normals through mid-April 2021. 

Nevada Reservoir Storage: Percent Capacity in 2020 vs. 2021

Bar graph of reservoir storage by percentage of capacity by basin in Nevada. All basins are showing % capacity less than last year.
Reservoir storage in Nevada by basin from the Natural Resources Cobnservation Service Water Supply Outlook Report. The bar graph shows the percent of the capacity that is filled in the previous year (green) and the current year (blue) as of April 1, 2021. 

Vegetation Drought Response Index (VegDRI)

CONUS map of the Vegetation Drought Index (VegDRI) for 4/11/2021. Areas where the vegetation conditions are in moderate to extreme drought are found in CA, NV, AZ, NM, ID, OR, WA, ND and TX.
Vegetation Drought Response Index (VegDRI) conditions from April 11, 2021.

3-Month Evaporative Demand Drought Index (EDDI)

 A California Nevada map of three month EDDI  for 4/10/2021. Areas where 3 month EDDI conditions are in extreme drought are found in Bakersfield, Imperial Valley, Riverside, Napa, Lake, Butte and Yapa counties. Moderate drought is through southern California and Nevada and along the California coast. Northeastern California and North western Nevada are showing wetness.
Three-month EDDI from April 10, 2021. The atmospheric thirst driving evapotranspiration has been high in southern California and Nevada and coastal California, further exacerbating the current drought by drying the landscape. Visit the Great Basin Dashboard for 1-month and 6-month EDDI maps. 

Drought Impacts

  • Current conditions continue to intensify and expand drought impacts. As the region heads into summer, agriculture, water supplies, recreation, and ecosystems are likely to be impacted. 
  • Condition Monitoring Observer Reports (CMOR) over the past month highlights poor pasture forage, animal stress, dry stock ponds, water hauling, winds pulling moisture from soils, irrigated orchards, and culling and selling cattle.
  • On March 5, the U.S. Secretary of Agriculture designated 50 California counties and 16 Nevada counties as primary natural disaster areas based on the U.S. Drought Monitor.

U.S. Secretary of Agriculture Disaster Designations

U.S. Secretary of Agriculture drought disaster designations by county across the U.S. USDA designated 50 California counties and 16 Nevada counties as primary natural disaster areas.
Secretarial disaster designations as of April 12, 2021. Source: U.S. Department of Agriculture Farm Service Agency.
  • On March 23, the California State Water Project reduced allocations to 5% of requested supplies and released a revised Drought Contingency Plan as the U.S. Bureau of Reclamation Central Valley Project reduced south-of-Delta allocations.
  • On March 22, the California State Water Resource Control Board mailed early warning notices to approximately 40,000 water right holders, urging them to plan for potential shortages by reducing water use and adopting practical conservation measures.
  • On April 14, the U.S. Department of Agriculture (USDA) announced the availability of up to $10 million in assistance from USDA’s Wildfire and Hurricane Indemnity Program Plus to assist agriculture producers impacted by the worsening drought conditions in the Klamath River Basin. The U.S. Bureau of Reclamation also released a Temporary Operations Plan and assistance.
  • Multiple media outlets are reporting that local water agencies and irrigation districts are considering voluntary or early stage drought actions. On the other hand, the Metropolitan Water District issued a statement that southern California is prepared for drought but is exploring purchasing supplies on the water market.  
  • Farmers have been encouraged to start planning now for potential water supply shortages later this year and to identify practical actions such as increasing water conservation measures, reducing irrigated acreage, managing herd size, using innovative irrigation and monitoring technologies, or diversifying water supply portfolios. California vineyards are also preparing for continued dry conditions. 
  • In preparation for this upcoming wildfire season, California will hire ~1,400 additional firefighters, and Gov. Newsom has signed a $526 million wildfire prevention plan. 
  • Drought contributed to recent Point Reyes Elk death, and other wildlife impacts are expected such as on waterfowl.

Report Your Drought Impacts

Drought and Climate Outlook

ENSO

NOAA’s ENSO alert system status is currently a La Niña advisory, with a transition from La Niña to ENSO-neutral likely in the next month or so, with an 80% chance of ENSO-neutral during May–July 2021. For more information, please check out the NOAA ENSO blog, including a look back at the 2020–2021 winter outlook performance.

Seasonal Drought, Temperature, and Precipitation Outlooks

With the close of the primary wet season in California-Nevada, drought is expected to persist or worsen if evaporative demand is high throughout spring and summer. The National Weather Service Climate Prediction Center forecasts through July have increased odds of above-normal temperatures with the highest odds centered on the 4 corners areas. Most of the region has equal chances of above/normal/below precipitation, including those areas impacted by the summer monsoon. S

Seasonal Drought Outlook

Climate Predication Center Seasonal Drought Outlook for April 15 to July 31, 2021. Drought is likely to persist or develop across California and Nevada.
U.S. Seasonal Drought Outlook for May to June 2021. Source: NOAA Climate Prediction Center.

Three-Month Temperature and Precipitation Outlooks

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

Climate Prediction Center 3-month precipitation outlook, valid for May to July 2021. Odds favor below-normal precipitation in northern California and Nevada, with equal chances of above, below, and normal precipitation in the rest of the two states.
May through July 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 CenterHow do I interpret these graphics? 

National Significant Wildland Fire Potential Outlook

Much of the West observed below average precipitation and cooler than normal temperatures in March. According to the National Interagency Fire Center’s Predictive Services, southern Nevada may see their fire season start in late May into June. The start of California’s fire season will depend on any extended dry spells combined with low humidity and windy weather. Upper elevations of California will be particularly vulnerable earlier than usual, as the state moves into July and the snowpack potentially melts off earlier than normal. Parts of California’s coast, from central to southern California, will also be at early fire potential due to fuels being abnormally dry.

National Significant Wildland Fire Potential Outlook for June 2021. Parts of southern Nevada show an increased risk for significant wildland fires.

National Significant Wildland Fire Potential Outlook for July 2021. Upper elevations in California, as well as parts of California's coast and eastern Nevada, show an increased risk for significant wildland fires.
June (top) and July (bottom) Significant Wildland Fire Potential Outlook from National Interagency Fire Center Predictive Services. Above normal indicates a greater than usual likelihood that significant fires will occur.

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. 

The next California-Nevada Drought & Climate Outlook webinar will be a special joint California and Southwest Drought Update and Wildfire Outlook Webinar. Register here to join us on Monday, May 24 at 11 a.m. PT.