● Record setting heat and dryness in March.
● Snowpack has dwindled to a mere 18% of normal, making it the second lowest on record.
● Precipitation outlook for April has a strong dry signal in climate models.
Details:
The 30-day precipitation totals ending March 30th left most of California completely dry.
Figure 1a 30-day precipitation totals through March 30, 2026. Source: WRCC
The 30-day temperature anomalies for March have been well outside the historical record.
Figure 1b – Average Monthly temperatures for SF American River (abv 5000’). Source: CNRFC Observed mean areal temperatures (deg F)
Extreme dry and warm conditions over the past 5 weeks have dropped the Statewide snowpack from 75% of average (Feb 20th) to 18% of average (March 30th). While 2015 had a smaller snowpack (5% on April 1), the 2026 snowpack is now ranked second lowest, less than the 2014 drought year.
Figure 2a CA snow water content by region. Source: CA Department of Water Resources
Trends in the water year forecasts for the Sacramento and San Joaquin Valley Water Resources Index locations have been trending flat the past few days, because forecast precipitation is expected to be near climatology. Today the Sacramento Water Supply Index forecast came in at 88% of average, and the San Joaquin Index is at 81% of average.
Figure 3a Water year forecast trends for the Sacramento Valley Water Supply Index. Source: CNRFC
Figure 3 Water year forecast trends for the San Joaquin Valley Water Supply Index. Source: CNRFC
The week of April 7-13, is expected to be warmer than normal and drier than normal.
Figure 4.a&b - Climate Prediction Center 8-14 Outlooks. Source: CNRFC and CNRFC
The outlook for April is currently dry across much of California and Nevada, based on the North American Multi-Model Ensemble (NMME). The same is true for the International Multi-Model Ensemble (IMME).
Figure 4.c. - Climate Prediction Center NMME precipitation anomalies for March. Source: CPC
Figure 4.d. - Climate Prediction Center IMME precipitation anomalies for April. Source: CPC
After a wet start to the water year, we have had two dry periods (5 weeks in Jan – Feb., and 5 weeks in late Feb. – March). The next couple days of wetter weather will “stop the bleeding” for a week or so, but warm weather in April will likely melt the remaining snow in most watersheds.
One can hope for a turn toward wetter weather, but the last 6 months of the water year (April – September) only account for 17% of the annual Sierra precipitation, on average. Any rainfall that does come after this long dry spell will fall on dry soil and not likely change the situation unless the precipitation is long in duration and very wet. Therefore, barring any extreme anomaly, our water supply for the remainder of the year is pretty much set.
Pete Fickenscher, CNRFC
