California-Nevada Drought Status Update

Current Conditions

• Conditions have greatly improved since the January 22 California-Nevada Drought and Climate Outlook webinar. Then, a warmer, drier start to the water year was buffered by carryover from last year’s wet conditions, such as soil moisture and reservoir storage. 
• Over the past 30 days, precipitation over California-Nevada has been above normal, with the exception of portions of the northern Sierra Nevada. Very little drought is present and only in southern Nevada.
• The atmospheric river (AR) that made landfall in early February alleviated water year precipitation deficits throughout much of the region that had accumulated in the fall and early winter. Prior to the event about 77% of the region was below normal water precipitation and after it was only 44% of the region. The Sierra Nevadas and Southern Nevada are still below normal. Read more from CW3E (Figure 1).
• Recent storms have improved snow drought conditions and the Sierra Nevada snowpack (Figure 2), but snow water equivalent remains below normal for this time of year. However, snow water equivalent is above normal in much of northern Nevada. 
• Soil moisture remains above normal throughout much of the region as carryover from a wet year and the recent storms.  

Figure 1. Percent of Normal Water Year to Date Precipitation: February 4 vs. February 7

Key Takeaway: The early February atmospheric river alleviated water year precipitation deficits throughout parts of the region.

Figure 2. Current Snow Conditions in In the Sierra Nevada Mountains

Key Takeaway: Snowpack throughout much of the Sierra Nevada Mountains is below normal, with about 50% of the stations below 70% of normal snow water equivalent (SWE) for this time of year. However, SWE is above normal in much of northern Nevada. 

Figure 3. Water Year 2024 Central Valley Aggregated Observed and Forecasted Streamflows 

Key Takeaway: Accumulated streamflows for the Central Valley have been close to the median and are forecasted to remain near normal for the reminder of the year. The two peak flows were observed January 23 and February 6, both related to landfalling atmospheric rivers.  

California-Nevada Drought Impacts

• Nevada reservoir capacity is much higher than last year. The State of Nevada total reservoir storage capacity is 64% and well above the median (Figure 4).
• Reservoir storage in the Western Sierras remains above normal, but when examined holistically with snowpack, it is below the 2000–2015 normal (Figure 5). Northern California snowpack plus reservoir water storage conditions are near normal, unlike in the Southern Sierra. California reservoir levels are primarily above historical averages. 
• Upper Colorado River Basin precipitation and snowpack conditions are near normal, as Lake Powell and Lake Mead levels are above what they were at this time last year.
• Despite improved conditions, some long-term drought impacts remain:
  • About one-third of California’s groundwater monitoring wells remain below normal levels, with significant decreasing trends over the past 20 years.
  • Ecosystem impacts remain, such as widespread tree mortality and and impacts to fisheries, such as occurred in the coastal salmon fishery last year.
• More information on drought’s impact to local economies is also coming to light, such as drought’s impacts on California National Park visitation.

Report your local drought impacts through a Condition Monitoring Observer Report:

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Figure 4. Reservoir Storage in Nevada

Key Takeaway: State of Nevada total reservoir storage capacity at the end of January is over 60% and more than double what it was at this time last year.

Figure 5. Water Stored in Western Sierra Reservoirs Plus Snowpack

Key Takeaway: The Western Sierra reservoir plus snowpack storage is 92% of normal for this time of year, with carryover from last year boosting reservoir levels at the beginning of the water year. Broken down by region, the Northern Sierra are at 103% of normal, Central Sierra are at 95% of normal and Southern Sierra are at 80% of normal.  

Outlooks and Forecasts for California-Nevada

• This ongoing wet pattern is expected to continue over the coming days and weeks. Temperatures will be key in determining the extent of snowpack building and snowmelt rates going into spring and summer.
• As of February 14, the short-term forecast (out to February 28) indicates above-normal precipitation with a possible return of hazardous precipitation, winds, and flooding to California later this week (Figure 6).
• The Climate Prediction Center’s seasonal forecasts (March through May) favor above-normal temperatures in Northern California-Nevada and equal chances of above-, below-, and near-normal precipitation across the region (Figures 7, 8).
• NOAA’s El Niño–Southern Oscillation (ENSO) alert system status is currently an El Niño Advisory. A transition from El Niño to ENSO-neutral is likely by April–June 2024 (79% chance), with increasing odds of La Niña developing in June–August 2024 (55% chance). For more information, check out the NOAA ENSO blog. 
• Drought conditions are not expected to develop in the next three months.

Figure 6. CW3E Probability Atmospheric River Landfall Tool

Key Takeaway: Additional atmospheric river precipitation is headed to the western U.S. coast over at least the next 7 days.

Figure 7. Seasonal (3-Month) Precipitation Outlook

Key Takeaway: Seasonal forecasts favor above-normal precipitation in Southern California-Nevada through Spring.

Figure 8. Seasonal (3-Month) Temperature Outlook

Key Takeaway: Seasonal forecasts favor above-normal temperatures in Northern California-Nevada through Spring.

Drought Early Warning Resources

Explore regional and state drought information:

California

Nevada

California-Nevada DEWS

Register for the March 25 California-Nevada Drought and Climate Outlook Webinar, which will provide an overview of climate and drought conditions, impacts, and outlooks.

Prepared By

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

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