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San Marcos Creek Set to Become a Feature Instead of a Foe

The largest project in the city of San Marcos is only a few weeks from completion.

The city dedicated millions of dollars and spent three years improving the area around San Marcos Creek, which runs through the center of town. The creek regularly flooded streets when it rained, prompting road closures and backed–up traffic.

California Faces Rapid Snowmelt From Heat Wave; Flood Fears in Yosemite, Elsewhere

After weeks of uncertainty, forecasters say an incoming California heat wave will trigger rapid snowmelt on the slopes of the Sierra Nevada and cause more flooding in portions of the San Joaquin and Owens valleys this week.

Temperatures in Central California are forecast to climb into the high 80s and mid-90s beginning Wednesday and into the weekend, with the potential for some areas to approach daily records.

As Epic Snow Melts, A California Community Braces for Floods

Ron Caetano is packed and ready to go. His family photos and valuables are in the trailer and he’s put food in carry totes. He moved the rabbits and chickens and their automatic feeders to higher ground.

Opinion: Catastrophic Floods and Breached Levees Reveal a Problem California Too Often Neglects

For much of the past decade, Californians have been fixated on drought, and rightly so. But the flipside of the state’s volatile climate returned this year, reminding us that “normal” in a land of extremes can be either very wet or very dry.

A dozen or more atmospheric rivers have caused more than $5 billion in damage in the state, with more damage expected when the Sierra Nevada snowpack melts in the coming weeks.

Pilot Project Aims to Divert Excess Water Runoff Potentially Caused by Massive Sierra Snowpack

For most of California’s history, a record snowpack in the Sierra has been like money in the bank — filling reservoirs and keeping rivers healthy and flowing year-round. But in this era of climate change, there’s a real concern that some of that precious water could slip through our fingers.

“If we get a very warm rain, or a series of warm rains — if we get an extended period of warm weather, that’s going to trigger the snowmelt and the flooding potential for the river,” said Central Valley rancher Don Cameron.

Sierra Nevada Snowpack: One of the Largest on Record

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 record snowpack and snow water equivalent is great news for water supply, there are concerns the record snowpack could create flooding issues.

Sierra Nevada Snowpack: One of the Largest on Record

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.

California Farmers Flood Their Fields in Order to Save Them

When Don Cameron first intentionally flooded his central California farm in 2011, pumping excess stormwater onto his fields, fellow growers told him he was crazy.

Today, California water experts see Cameron as a pioneer. His experiment to control flooding and replenish the ground water has become a model that policy makers say others should emulate.

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

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 Spring Outlook-drought-snowpack-flooding

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

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.