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Regional Drought Update Date
February 5, 2021
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Drought Status Update

Drought Status Update for California-Nevada

DEWS Regions:
California Nevada
States:
California, Nevada
Update Status:

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

Recent storms bring much-needed snow and rain, but drought continues. 

 

  • Moderate-to-Extreme Drought remains across California and Nevada, which typically receive about half of their precipitation in December through February.
  • Recent storms have brought some relief to the region, increasing snow pack and moistening soils. The storms were not enough to remove long-term drought conditions and impacts.
  • Preparation for continued drought impacts (e.g., pasture conditions, water supply, fire risk) should be considered, especially in the driest areas. Recent improvements may be temporary as dryness returns and long-term water deficits in the region continue.
Current Conditions
U.S. Drought Monitor Conditions: California-Nevada | February 2, 2021
U.S. Drought Monitor

U.S. Drought Monitor Categories

Last Updated: 02/02/21
Main Stats
86%
of California is experiencing Moderate to Exceptional Drought (D1-D4)
27,022,164
people in California are in Moderate to Exceptional (D1 - D4) Drought
99.7%
of Nevada is experiencing Moderate to Exceptional Drought (D1-D4)
2,700,553
people in Nevada are in Moderate to Exceptional (D1 - D4) Drought

Current Conditions

  • According to the U.S. Drought Monitor, drought conditions over the last 2 weeks intensified in Nevada and improved over coastal, central, and northern California. Long-term precipitation deficits from Water Year 2020 remain throughout the region.

Learn More About Short- vs. Long-Term Drought

  • The La Niña pattern that developed in the tropical Pacific in Autumn 2020 remains firmly in place. Over the historical record, La Niña tilts odds toward wetter water years in the Pacific Northwest and drier water years in the Southwest U.S. There is large uncertainty in the northern parts of California and Nevada.
  • An atmospheric river that made landfall in central California and stalled before moving south brought widespread precipitation to the region, with central California and western, northern Nevada receiving the most precipitation from the storm. 
  • According to the California Department of Water Resources, the statewide average snow water equivalent (SWE) of the Sierra Nevada snowpack climbed to 12.5 inches (70% of normal) by February 2, up from about 6 inches (less than 40%) just 10 days earlier. The Feb. 3rd Phillips Station manual snow survey recorded SWE of 93% of average for that location. SWE values remain below normal across the Sierras and the Colorado River Basin. 
  • Most reservoir levels are below normal in the northern, central, and southern Sierras, and Lake Tahoe is approaching normal levels for this time of year. 
  • The odds of reaching normal precipitation for the water year are now less than 10% in parts of California-Nevada, with almost the entire region having odds of less than 30%. 

Percent of Normal Precipitation

Two images show the percent of normal precipitation for California and Nevada through 2/3/2021. For the past 14 days (left image), most of CA-NV shows >100% of normal except for the CA-OR border, northeast Nevada, and interior southeastern CA. Since the start of the water year (right image), the percent since the start of the water year shows most of CA-NV below 50%-70% or less of normal with small areas between 80%-90%.
Percent of normal precipitation for the last 14 days (left) and since the start of water year (right). Valid through February 3, 2021. Source: High Plains Regional Climate Center.

Total Precipitation Excess/Deficit Since October 1, 2019

California-Nevada map showing total precipitation excess or deficit from PRISM data since 10/2/2019 to 2/3/2021. Much of NV, N. CA, the Sierras, and coastal CA (except near San Diego) show precipitation deficits in the 10s of inches.
Total precipitation excess or deficit from PRISM data since the start of 2020 Water Year (October 1, 2019). Source: C. Castellano, CW3E.

Snow Water Equivalent Percent of Median

A map of the western U.S. showing the percent of 1981-2020 median snow water equivalent values from the NRCS from 2/2/2021. SWE in the region is primarily between 50% and 75%, including the Sierras (73-84% at the basin scale%).
Snow water equivalent percent of 1980-2010 median as of February 2, 2021. For an interactive version of this map, please visit NRCS.

Evaporative Demand Drought Index (EDDI): 1 Month, 3 Month, 6 Month

A map of California-Nevada showing the Evaporative Demand Drought Index (EDDI) at a 1-month time scale as of 01/30/2021. A colorbar scale ranges from ED4 (red, 100% drought) to EW4 (blue, 0%). At 1-month, EDDI shows values of ED0-ED4 in southern coastal CA and southern NV.
1-Month Evaporative Demand Drought Index (EDDI), as of January 30, 2021. Source: NOAA/Earth System Research Laboratories, Great Basin Dashboard.

 

A map of California-Nevada showing the Evaporative Demand Drought Index (EDDI) at a 3-month time scale as of 01/30/2021. A colorbar scale ranges from ED4 (red, 100% drought) to EW4 (blue, 0%). At 3 months, EDDI shows values of ED0-ED4 across most of CA-NV except for northernmost NV and near the northern CA-NV border.
3-Month Evaporative Demand Drought Index (EDDI), as of January 30, 2021. Source: NOAA/Earth System Research Laboratories, Great Basin Dashboard.

 

A map of California-Nevada showing the Evaporative Demand Drought Index (EDDI) at a 3-month time scale as of 01/30/2021. A colorbar scale ranges from ED4 (red, 100% drought) to EW4 (blue, 0%). At 6 months, EDDI shows values of ED0-ED4 across all of CA-NV with ED3-ED4 conditions predominant.
6-Month Evaporative Demand Drought Index (EDDI), as of January 30, 2021. Source: NOAA/Earth System Research Laboratories, Great Basin Dashboard.

California/Nevada Soil Moisture Drought Intensity: February 2, 2021

A map of California-Nevada shows soil moisture drought intensity from 2/2/2021. Values range from None (30%) (white), D0 (11.7%) (yellow), D1 (19.7%) (tan), D2 (15.9%) (orange), D3 (12.1%) (red), to D4 (10.7%) (dark red). D3-D4 is present predominantly over parts of the Sierra and southern NV and near the CA-AZ and CA-OR borders. D0-D2 is present over much of the remaining area with the exception of central CA.

Soil moisture drought intensity for California and Nevada. Valid February 2, 2021. Source: UCLA Drought Monitor.

Water Storage in the Western Sierra Nevada and Lake Tahoe

Two time series graphics 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 as well as (above rim) Lake Tahoe. The reservoir normal peaks near May 1 for the Sierra and June 1 for Lake Tahoe while the reservoir+snowpack normal peaks April 1. In the Western Sierra, reservoir normals are below normal and reservoir+snowpack are well below normal while Lake Tahoe is near normal.
Water storage compared to 1981-2010 is below normal in the Western Sierra Nevada (top) and in Lake Tahoe (bottom) through February 1, 2021. Source: CNAP Water Storage Tracking.

Odds of Water Year 2021 Reaching Various Fractions of Water Year Normal Precipitation Totals

These maps show odds of water year 2021 reaching 50%, 75%, 100%, 125%, or 150% of water year normal precipitation as of February 1, 2021 for the western U.S. Most of California and Nevada have 10%-30% odds of reaching 100% of normal precipitation and have 30%-80% odds for reaching 75% of normal precipitation.
The odds of reaching normal precipitation based on historical water year totals. The dry start to the water year means the odds of reaching 100% normal precipitation is between <10%-30% throughout the region. Learn more about the product on the CW3E website. 

Drought Impacts

Recent news and articles from the California Department of Water Resources:

Report Your Drought Impacts

Drought & Climate Outlook

ENSO

NOAA’s ENSO alert system status is currently a La Niña advisory and is likely to continue through the Northern Hemisphere winter 2020-21 (~95% chance during January-March), with a potential transition to ENSO-neutral during the spring of 2021 (55% chance during April-June). For more information, please check out the NOAA ENSO blog and the Western Regional Climate Center handout about the La Niña impacts for the West.

Monthly Drought Outlook

The monthly drought outlook (released Jan. 31) takes into account the late January to early February storminess. The outlook shows drought persistence over Nevada. In California, as a result of these storms, potential short-term improvement is depicted but may be fleeting as dry conditions return.  

Climate Predication Center Monthly Drought Outlook for February 2021, predicting the probability that drought will emerge, stay the same, or get better. It is probable that drought will either be removed or remain but improve in areas of north and central California.
U.S. Monthly Drought Outlook for February 2021. Source: NOAA Climate Prediction Center.

Temperature & Precipitation

The NOAA Climate Prediction Center's short-term to seasonal forecasts favor a return of dry conditions with a return of a “typical” La Niña pattern and a dry southwest. A return to dryness would continue to build drought impacts in February, climatologically one of the wettest months for the region.

Climate Prediction Center 1-Month Outlooks

Climate Prediction Center 1-month precipitation outlook, valid for February 2021. Shows probability of below-normal precipitation throughout most of California and the western edge of Nevada.

Climate Prediction Center 1-month temperature outlook, valid for February 2021. Shows probability of below-normal temperatures throughout most of California and Nevada.
February 2021 monthly precipitation outlook (top) and temperature 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? 

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) and the California-Nevada Applications Program, a NOAA RISA team, 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. 

Register here for the next California-Nevada Drought & Climate Outlook webinar on March 22, 2021 at 11 am PDT.

Partner(s)
NOAA emblem

National Oceanic and Atmospheric Administration (NOAA)

California-Nevada Adaptation Program.

California-Nevada Adaptation Program (A NOAA CAP/RISA Team)

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