After a dry start to the year, March storms provided a boost to snowpack that was evident in the fourth Sierra snow survey conducted for 2024.

The Department of Water Resources (DWR) conducted the all-important April snow survey earlier this week, the fourth measurement of the season at Phillips Station. The manual survey recorded 64 inches of snow depth and a snow water equivalent of 27.5 inches, which is 113 percent of average for this location. The snow water equivalent measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast. The April measurement is critical for water managers as it’s considered the peak snowpack for the season and marks the transition to spring snowmelt into the state’s rivers and reservoirs.

DWR’s electronic readings from 130 stations placed throughout the state indicate that the statewide snowpack’s snow water equivalent is 28.6 inches, or 110 percent of the April 1 average, a significant improvement from just 28 percent of average on Jan. 1.

The focus now shifts to forecasting spring snowmelt runoff and capturing as much of that water as possible for future use.

“It’s great news that the snowpack was able to catch up in March from a dry start this year. This water year shows once again how our climate is shifting, and how we can swing from dry to wet conditions within a season,” said DWR Director Karla Nemeth. “These swings make it crucial to maintain conservation while managing the runoff. Variable climate conditions could result in less water runoff into our reservoirs. 100 percent snowpack does not mean 100 percent runoff. Capturing and storing what we can in wetter years for drier times remains a key priority.”

California’s reservoirs remain in good shape thanks to state efforts to capture and store as much water as possible from record storms in 2023 and again this season. The State Water Project has increased storage by 700,000 acre-feet at Lake Oroville and by 154,000 acre-feet at San Luis Reservoir since Jan. 1. Locally, Don Pedro Reservoir is at 802 feet, about 102% of normal. Statewide, reservoir levels currently stand at 116 percent of average.

However, there are challenges ahead as the spring runoff begins. The dry start to the year, soot and ash from burn scars that accelerates snowmelt, and other factors may result in below average spring runoff which can impact water availability.

Recently, the State Water Project increased its forecasted allocation of water supplies for the year to 30 percent, up from an initial 10 percent, due to the storms in February and March. However, uncertainty about the spring runoff and ongoing pumping restrictions to protect threatened and endangered species in the Delta has impacted that allocation forecast.

“California has had two years of relatively positive water conditions, but that is no reason to let our guard down now,” said Dr. Michael Anderson, State Climatologist with DWR. “With three record-setting multi-year droughts in the last 15 years and warmer temperatures, a well above average snowpack is needed to reach average runoff. The wild swings from dry to wet that make up today’s water years make it important to maintain conservation while managing the runoff we do receive. Our water years moving forward will see more extreme dry times interrupted by very wet periods like we saw this winter.”

That need to adapt to a changing climate is why Governor Gavin Newsom joined the April 2 snow survey at Phillips Station to announce the release of the California Water Plan Update 2023. The Water Plan Update sets forth a vision for all Californians to benefit from water resources that are sustainable, resilient to climate change and achieves equity for all communities and benefits the environment. Check out the Water Plan Update to learn more about how the plan focuses on key issues including addressing climate urgency, strengthening watershed resilience, and achieving equity in water management.

As part of the state’s climate adaptation efforts, over the past two years, California has worked with local groundwater agencies and state and federal partners to capture as much water as possible to prepare for the next drought. In 2023, more than 1.2 million acre-feet of groundwater recharge was permitted by state agencies, with nearly 400,000 acre-feet of flood water recharged using the Executive Orders issued by Governor Newsom.

On average, the Sierra snowpack supplies about 30 percent of California’s water needs. Its natural ability to store water is why the Sierra snowpack is often referred to as California’s “frozen reservoir.” Data from these snow surveys and forecasts produced by DWR’s Snow Surveys and Water Supply Forecasting Unit are important factors in determining how DWR provides water to 27 million Californians and manages the state’s water resources.

DWR conducts five snow surveys at Phillips Station each winter near the first of each month, January through April and, if necessary, May.

For California’s current hydrological conditions, visit https://cww.water.ca.gov.