{"id":232763,"date":"2026-03-23T16:36:07","date_gmt":"2026-03-23T16:36:07","guid":{"rendered":"https:\/\/www.newsbeep.com\/us-ca\/232763\/"},"modified":"2026-03-23T16:36:07","modified_gmt":"2026-03-23T16:36:07","slug":"record-heat-melting-snow-and-what-it-all-means-for-californias-reservoirs","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us-ca\/232763\/","title":{"rendered":"Record heat, melting snow, and what it all means for California’s reservoirs"},"content":{"rendered":"

This story <\/a>was originally published by CalMatters. Sign up<\/a> for their newsletters.<\/p>\n

A record-baking heat wave has been scalding California, with major consequences for the state\u2019s most important reservoir: its snowpack.\u00a0<\/p>\n

Providing about a third<\/a> of the state\u2019s water supply, the Sierra Nevada snowpack is a vital source of spring and summer runoff that refills reservoirs when the state needs the water most.\u00a0<\/p>\n

But a warm wet storm followed February\u2019s snow, and now, March temperatures<\/a> are shattering records \u2014 prompting warnings of rapid snowmelt and swift rivers.\u00a0<\/p>\n

Historically, the snowpack is at its deepest in April<\/a>. But climate change is shifting runoff earlier<\/a>, leaving less water trickling down the mountains<\/a> in warmer months for homes, farms, fish, hydropower and forests.\u00a0<\/p>\n

\u201cIn an ideal world, you\u2019d have your reservoir full right now, and this additional huge snowpack reservoir that we know will help replenish and provide more water supply,\u201d said Levi Johnson, operations manager for the Central Valley Project<\/a>, the massive federal water system that funnels northern California river water to the Central Valley and parts of the Bay Area.\u00a0<\/p>\n

This year, he said, \u201cwe\u2019re not going to have that.\u201d\u00a0<\/p>\n

California\u2019s reservoirs are in good shape, brimming above historic averages<\/a> with many nearing capacity. But that summertime snow bank on the slopes of the Sierra Nevada is disappearing early, and fast \u2014 dropping to 38% of average for mid-March<\/a> statewide.<\/p>\n

It\u2019s not yet the worst snowpack on record: that distinction belongs to 2015, when then-Gov. Jerry Brown stood on brown, barren slopes of the Sierra Nevada to watch scientists measure the most meager snowpack in history.\u00a0\u00a0<\/p>\n

But this year\u2019s snowpack is rapidly approaching the worst five on record for April 1st, state climatologist Michael Anderson said \u2014 and it\u2019s likely to worsen still as temperatures climb. From early to mid-March, the snowpack has been disappearing at a rate of roughly 1% per day.\u00a0<\/a><\/p>\n

It\u2019s a sharp departure from the near-average conditions of last year<\/a>, and presents both a challenge and a glimpse of the future for reservoir operators in the state.\u00a0<\/p>\n

Conflicting roles for reservoirs<\/p>\n

Many of California\u2019s reservoirs serve a dual role: stoppering flood flows and storing water for drier times ahead.\u00a0<\/p>\n

Those roles sometimes conflict \u2014 as they did at Lake Mendocino, which dried to a mud puddle during the 2012\u201316 drought. Rigid federal operating rules forced the U.S. Army Corps of Engineers to release vital water supplies from the dam to make room for winter floods that didn\u2019t come.\u00a0<\/p>\n

The dire water shortages that followed spurred an experimental partnership<\/a>called Forecast Informed Reservoir Operations, between the Scripps Institution of Oceanography at UC San Diego\u2019s Center for Western Weather and Water Extremes and state, federal and local agencies.\u00a0<\/p>\n

The program incorporates advanced forecasting and weather observations into reservoir release decisions at Lake Mendocino. It prevented the reservoir from going dry during the most recent drought, according to Don Seymour, deputy director of engineering at Sonoma Water, which co-manages the reservoir.\u00a0<\/p>\n

Now, 165 miles away in the Sierra Foothills, Yuba Water Agency is eyeing adopting the same program<\/a> for New Bullards Bar, a reservoir roughly eight times bigger than Lake Mendocino that\u2019sfed by Sierra snowmelt on the North Yuba River.\u00a0<\/p>\n

The reservoir supplies water to more than 60,000 acres of farmland in Yuba County as well as users south of the Delta. But early snowmelt is complicating efforts to store that water.\u00a0<\/p>\n

\u201cWe\u2019re seeing snowmelt conditions in mid-March that we normally don\u2019t see until at least mid-May,\u201d said general manager Willie Whittlesey. \u201cIt\u2019s pretty obvious that this is the runoff \u2014 this is the snowmelt \u2014\u00a0and it\u2019s just happening about two months early.\u201d\u00a0<\/p>\n

The reservoir is nearly full at 114% of average for this date<\/a> and 84% of total capacity.\u00a0<\/p>\n

But when snowmelt arrives early, the agency can\u2019t catch it once the reservoir reaches a certain level \u2014 even when no storms are in the immediate forecast. Federal rules require Yuba Water to maintain a certain amount of empty space until June to absorb potential floodwaters, according to Whittlesey.\u00a0<\/p>\n

Yuba Water is working with the U.S. Army Corps of Engineers to update this decades-old rulebook, Whittlesey said, but until then it must request special permission to store the extra water.\u00a0<\/p>\n

Though the agency has received permission in the past, this year it\u2019s also contending with a rupture in a major pipe to one of its hydropower facilities, which is forcing the agency to hold back more water behind the dam.\u00a0<\/p>\n

Whittlesey said he suspects that the combination of flood-control requirements and damage control after the pipe failure is likely costing them tens of thousands of acre-feet of snowmelt.\u00a0<\/p>\n

The California Department of Water Resources, which manages Lake Oroville \u2014 the state\u2019s second-largest reservoir \u2014 told CalMatters that it\u2019s storing water beyond its normal flood control limits, with permission from the U.S. Army Corps of Engineers.<\/p>\n

In the Bay Area, the East Bay Municipal Utility District, California\u2019s second-largest urban water supplier, owns and operates the Camanche<\/a> and Pardee reservoirs<\/a> in the Central Sierra foothills.\u00a0<\/p>\n

\u201cWe\u2019re working to save every drop in light of the warm temperatures that we are experiencing now, and in light of all the zeros that we are seeing in terms of a rain or snow forecast,\u201d said spokesperson Andrea Pook. \u201cThe last time that we had run off this early was in 2015.\u201d<\/p>\n

Pook said the district is releasing less water from its reservoirs now, in order to preserve more for the fall when salmon migrate upriver to spawn.\u00a0<\/p>\n

\u201cWe\u2019re tracking to not necessarily be in a drought situation. But I am not convinced that we\u2019re going to fill our reservoirs by July 1st, which is our usual goal,\u201d Pook said.\u00a0<\/p>\n

Improved forecasts after a major miss<\/p>\n

Even as California suffers record heat and early snowmelt, the state is better prepared than in the past.\u00a0<\/p>\n

Five years ago, state forecasters badly missed their runoff predictions<\/a> \u2014 overestimating the snowmelt expected to refill reservoirs by up to 68%. Dry soils and a parched atmosphere drank up the runoff before it could flow into storage. Farms and cities scrambled in the middle of a drought as supplies fell far short of expectations.<\/p>\n

This year is different. Major reservoirs are already above historic averages<\/a>, and early season storms soaked the soil beneath the snowpack, making it less likely to swallow the runoff.\u00a0<\/p>\n

The state has also been working on better forecasts.\u00a0<\/p>\n

\u201cThings have substantially improved,\u201d said Andrew Schwartz, Director of UC Berkeley\u2019s Central Sierra Snow Laboratory, in an email to CalMatters.\u00a0<\/p>\n

Johnson, at the federal Central Valley Project, said that the state and federal water delivery systems are in a better spot than five years ago, and that forecasts haven\u2019t made a major miss since.\u00a0<\/p>\n

But the season\u2019s early melt may still leave a gap.<\/p>\n

\u201cIt\u2019s going to get us through this year just fine,\u201d Johnson said. \u201cBut it\u2019s not as ideal as having that additional snow reservoir ready to run off through summer, and replenish what we\u2019re going to be releasing.\u201d\u00a0<\/p>\n

Improved snowpack modeling and soil moisture estimates<\/a>, experimental temperature measurements at different snow depths, university collaborations and incorporating weather outlooks are helping, according to the Department of Water Resources<\/a>.\u00a0<\/p>\n

Still, between state budget shortfalls and federal cuts, challenges remain, Anderson said.<\/p>\n

Efforts to install more soil moisture sensors in national forests have run into permitting slowdowns at the U.S. Forest Service, which has shed thousands of employees<\/a> under President Donald Trump.\u00a0<\/p>\n

\u201cYou wait in line a lot longer,\u201d Anderson said. \u201cThat\u2019s been the biggest limitation of late. There just isn\u2019t anybody there.\u201d<\/p>\n

CalMatters<\/a> is a nonpartisan and nonprofit news organization bringing Californians stories that probe, explain and explore solutions to quality of life issues while holding our leaders accountable.<\/p>\n","protected":false},"excerpt":{"rendered":"This story was originally published by CalMatters. Sign up for their newsletters. A record-baking heat wave has been…\n","protected":false},"author":2,"featured_media":232764,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28],"tags":[443,642,19931,74,76,75,36221],"class_list":["post-232763","post","type-post","status-publish","format-standard","has-post-thumbnail","category-san-diego","tag-climate-change","tag-drought","tag-heat-wave","tag-san-diego","tag-san-diego-headlines","tag-san-diego-news","tag-snowpack"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/232763","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=232763"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/232763\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/232764"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=232763"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=232763"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=232763"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}