Tag Archive for: Climate Change

Sierra Nevada Snowpack: One of the Largest on Record

/in , /by /California Department of Water Resources / WNN

Following three consecutive years of drought in California, the Sierra Nevada snowpack is one of the most bountiful in more than 40 years. While the snowpack and snow water equivalent is great news for water supply, there are concerns the record snowpack could create flooding issues.

The California Department of Water Resources electronic readings from 130 snow sensors placed throughout the state indicate the statewide Sierra Nevada snowpack’s snow water equivalent is 61.1 inches, or 237% of average for April 3. The snow water equivalent measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast.

Sierra Nevada snowpack

This year’s April result from the statewide snow sensor network is higher than any other reading since the snow sensor network was established in the mid-1980s. Before the network was established, the 1983 April 1 statewide summary from manual snow course measurements was 227% of average. The 1952 April 1 statewide summary for snow course measurements was 237% of average.

“This year’s severe storms and flooding is the latest example that California’s climate is becoming more extreme,” said DWR Director Karla Nemeth after the April 3 snow survey at Phillips Station in the Sierra Nevada. Photo: Fred Greaves/California DWR

“California’s climate is becoming more extreme”

“This year’s severe storms and flooding is the latest example that California’s climate is becoming more extreme,” said DWR Director Karla Nemeth. “After the driest three years on record and devastating drought impacts to communities across the state, DWR has rapidly shifted to flood response and forecasting for the upcoming snowmelt. We have provided flood assistance to many communities who just a few months ago were facing severe drought impacts.”

Just as the drought years demonstrated that California’s water system is facing new climate challenges, this year is showing how the state’s flood infrastructure will continue to face climate-driven challenges for moving and storing as much of these flood water as possible.

Sierra Nevada snowpack-snow survey-DWR-

“This year’s result will go down as one of the largest snowpack years on record in California,” said Sean de Guzman, manager of DWR’s Snow Surveys and Water Supply Forecasting Unit. (R-to-L: de Guzman, Jacob Kollen, Water Resources Engineer in Snow Surveys and Water Supply Forecasting Unit, and Jordan Thoennes, Water Resources Engineer in Snow Surveys and Water Supply Forecasting Unit.) Photo: Kenneth James/California DWR

“One of the largest snowpack years on record”

“This year’s result will go down as one of the largest snowpack years on record in California,” said Sean de Guzman, manager of DWR’s Snow Surveys and Water Supply Forecasting Unit. “While 1952’s snow course measurements showed a similar result, there were fewer snow courses at that time, making it difficult to compare to today’s results. Because additional snow courses were added over the years, it is difficult to compare results accurately across the decades with precision, but this year’s snowpack is definitely one of the biggest the state has seen since the 1950s.”

Sierra Nevada-snowpack-April 2023-DWR

Snowpack varies by region

For California’s snow course measurements, only 1952, 1969 and 1983 recorded statewide results above 200% of the April 1 average. While above average across the state this year, snowpack varies considerably by region. The Southern Sierra snowpack is currently 300% of its April 1 average and the Central Sierra is at 237% of its April 1 average. However, the critical Northern Sierra, where the state’s largest surface water reservoirs are located, is at 192% of its April 1 average.

Flooding and spring snowmelt

The size and distribution of this year’s snowpack is also posing severe flood risk to areas of the state, especially the Southern San Joaquin Valley. DWR’s State-Federal Flood Operations Center (FOC) is supporting emergency response in the Tulare Lake Basin and Lower San Joaquin River by providing flood fight specialists to support ongoing flood response activities and by providing longer-term advanced planning activities.

The FOC and DWR’s Snow Surveys and Water Supply Forecasting Unit are helping local agencies plan for the spring snowmelt season by providing hydraulic and hydrologic modeling and snowmelt forecasts specific to the Tulare Lake Basin that are informed by DWR’s snowmelt forecasting tools, including Airborne Snow Observatory (ASO) surveys.

Storms this year have caused impacts across the state including flooding in the community of Pajaro and communities in Sacramento, Tulare, and Merced counties. The FOC has helped Californians by providing over 1.4 million sandbags, over 1 million square feet of plastic sheeting, and over 9,000 feet of reinforcing muscle wall, across the state since January.

State Water Project deliveries increased

On March 24, DWR announced an increase in the forecasted State Water Project deliveries to 75%, up from 35% announced in February, due to the improvement in the state’s water supplies. Governor Gavin Newsom has rolled back some drought emergency provisions that are no longer needed due to improved water conditions, while maintaining other measures that continue building up long-term water resilience and that support regions and communities still facing water supply challenges.

Sierra Nevada Snowpack-April 2023-Reservoir conditions

Water supply challenges

While winter storms have helped the snowpack and reservoirs, groundwater basins are much slower to recover. Many rural areas are still experiencing water supply challenges, especially communities that rely on groundwater supplies which have been depleted due to prolonged drought.

Water conservation ‘a way of life’

Long-term drought conditions in the Colorado River Basin will also continue to impact the water supply for millions of Californians. The state continues to encourage Californians to make water conservation a way of life as more swings between wet and dry conditions will continue in the future. The San Diego County Water Authority and its 24 member agencies provide rebates and programs to encourage water conservation.

Given the size of this year’s snowpack with more snow in the forecast, DWR anticipates conducting a May snow survey at Phillips Station. That is tentatively scheduled for May 1.

Opinion: Newsom Denies the Obvious: California is No Longer in Drought

/in , , /by /Los Angeles Timesby George Skelton

Gov. Gavin Newsom came close but couldn’t quite bring himself to say it: The drought’s over.

It’s disappointing when a governor won’t acknowledge what ordinary citizens already know because they can see things for themselves.

Another drought will emerge soon enough. It always does. That’s the California pattern — climate change or not.

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Opinion: Western Water Crisis Solutions Inevitably End With a Lot Less for California Farms

/in , , /by /CalMattersby Jim Newton

A modest proposal for western water: Turn off the spigot to the Imperial Valley and let the farms go fallow. In return, provide a water future for Arizona, Nevada and Southern California.

Sure, there would be a price to pay. California’s Imperial Valley, which sits in the southeastern corner of the state, bordered by Arizona and Mexico, produces alfalfa, lettuce, corn and sugar beets, among other crops. It’s home to more than 300,000 head of cattle. Cutting off the water would end all of that, along with the livelihoods of the farmers and ranchers who produce it and the communities that depend on it.

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Western Lawmakers Form Caucus to Talk Colorado River in Congress

/in , , /by /KUNCby Alex Hager

Members of Congress from six of the seven states that use Colorado River water are convening a new caucus. The group aims to help rally federal funding for water projects along a river that supplies 40 million people and is shrinking due to climate change.

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California Extreme Weather is the New Normal

/in , , /by /Newsweekby Robyn White

California’s bout of extreme wet weather could become the new normal as climate change worsens, a researcher has warned.

A bomb cyclone battered the state on Tuesday, bringing down trees and power lines. At least one person was killed after a tree fell onto a vehicle, the Los Angeles Times reported. Early on Wednesday, more than 130,000 customers were still without power, according to PowerOutage.us.

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Solutions for Building Water Resilience in California

/in , , /by /Maven's Notebookby Heather Cooley

With the ever-changing climate and increasingly dry summers, California faces water challenges, despite this year’s bountiful snowpack. At the February meeting of the California Water Commission, Heather Cooley, Director of Research at the Pacific Institute, explained how increasing water efficiency, water reuse, and stormwater capture is essential to building and enhancing California’s water resilience.

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NOAA Spring Outlook-drought-snowpack-flooding

NOAA Spring Outlook: California Drought Cut by Half with More Relief to Come

/in , /by /NOAA

NOAA’s U.S. Spring Outlook indicates the abnormally wet winter will further improve drought across much of the western U.S. as the snowpack melts in the coming months. Winter precipitation, combined with recent storms, wiped out exceptional and extreme drought in California for the first time since 2020, and is expected to further improve drought conditions this spring.

Significant flooding in the western U.S., especially in California, followed another series of strong Pacific storms that battered the region in March, and piled on to an already historic snowpack.

NOAA’s U.S. Spring Outlook highlights temperature, precipitation, drought and flood predictions for April through June to help the nation prepare for potential weather and climate threats to lives and livelihoods.

Climate change – wet and dry extremes

​“Climate change is driving both wet and dry extremes, as illustrated by NOAA’s observations and data that inform this seasonal outlook,” said NOAA Administrator Rick Spinrad, Ph.D.​​ “​Under the Bipartisan Infrastructure Law​ and Inflation Reduction Act, and in support of the Biden Administration’s priority to tackle the climate crisis​, NOAA ​will invest significant resources ​to build a Climate-Ready Nation that gives communities tailored information about changing conditions so that residents and economies are protected.”

Spring Outlook for drought, temperature and precipitation

On March 9, NOAA forecasters declared La Niña over. The El Niño-Southern Oscillation (ENSO) is a climate pattern, based on changes in rainfall and sea surface temperatures across the equatorial Pacific Ocean, that influences temperature and precipitation around the world. La Niña occurs when ocean temperatures are cooler than normal and rainfall is reduced in the eastern to central Pacific Ocean.

El Niño and La Niña

“La Niña has finally ended after being in place nearly continuously for more than two years,” said Jon Gottschalck, chief of the operational prediction branch at NOAA’s Climate Prediction Center, a division of the National Weather Service. “ENSO-neutral —  the transition period between El Niño and La Niña — is likely to continue into the early summer with elevated chances of El Niño developing thereafter. ENSO-neutral is factored into NOAA’s Spring Outlook.”

Moderate to exceptional drought coverage across the U.S. is at its lowest since August 2020 and is likely to continue improving, or end entirely, across much of California and the Great Basin. The spring wet season is expected to improve drought conditions across parts of the northern and central Plains. Current drought conditions in Florida are expected to improve or go away during the next three months.

Areas of extreme to exceptional drought across parts of the southern High Plains are likely to persist through the spring season, with drought also expected to develop into parts of New Mexico. Across parts of the Northwest U.S. and northern Rockies, drought conditions are also expected to continue. Drought may develop into parts of Washington state.

Above-average temperatures are favored for much of the southern and eastern half of the U.S. For April through June, the greatest chance for above-average temperatures exists from the southern High Plains eastward to Florida, and northward along the East Coast. Above-average temperatures are also likely for Hawaii and northern parts of Alaska. Below-average temperatures are predicted for the central Great Basin and the northern Plains.

California endures flooding, landslides, and evacuations

Parts of central and southern California that were still reeling from heavy snowfall earlier this month received yet another powerful atmospheric river which exited the region on March 15. Flooding, landslides, power outages, and evacuations are among the many impacts residents faced from the recent storm. The above graphic depicts most of the state receiving between 300-600% of normal precipitation over the last seven days. — USDA Water and Climate Update

Below-average precipitation like for the Southwest

NOAA forecasters predict above-average precipitation this spring across the Great Lakes, Ohio Valley, and into parts of the mid-Atlantic and Northeast. Below-average precipitation is most likely for the Southwest and parts of the Pacific Northwest.

How Rising Temperatures Are Intensifying California’s Atmospheric Rivers

/in , , /by /Gristby Jake Bittle

California is no stranger to big swings between wet and dry weather. The “atmospheric river” storms that have battered the state this winter are part of a system that has long interrupted periods of drought with huge bursts of rain — indeed, they provide somewhere between 30 and 50 percent of all precipitation on the West Coast.

The parade of storms that has struck California in recent months has dropped more than 30 trillion gallons of water on the state, refilling reservoirs that had sat empty for years and burying mountain towns in snow.

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Opinion: Why Rain-On-Snow Floods From Atmospheric Rivers Could Get Much Worse

/in , , /by /Los Angeles Timesby Keith Musselman

California’s latest atmospheric rivers are sending rainfall higher into the mountains and onto the state’s crucial snowpack. The rain alone is a problem for low-lying areas already dealing with destructive flooding, but the prospect of rain on the deep mountain snow has triggered widespread flood warnings.

When rain falls on snow, it creates complex flood risks that are hard to forecast. Those risks are also rising with climate change.

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Scientists Confirm Global Floods and Droughts Worsened by Climate Change

/in , , /by /PBSby Isabella O'Malley

The intensity of extreme drought and rainfall has “sharply” increased over the past 20 years, according to a study published Monday in the journal Nature Water. These aren’t merely tough weather events, they are leading to extremes such as crop failure, infrastructure damage and even humanitarian crises.

The big picture on water comes from data from a pair of satellites known as GRACE, or Gravity Recovery and Climate Experiment, that were used to measure changes in Earth’s water storage — the sum of all the water on and in the land, including groundwater, surface water, ice, and snow.

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