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California Snowlines On Track To Be 1,600 Feet Higher by Century’s End

This winter produced record snowfall in California, but a new study suggests the state should expect gradually declining snowpacks, even if punctuated with occasional epic snowfalls, in the future.

An analysis by Tamara Shulgina, Alexander Gershunov, and other climate scientists at UC San Diego’s Scripps Institution of Oceanography suggest that in the face of unabated global warming, the snowlines marking where rainfall turns to snow have been rising significantly over the past 70 years. Projections by the researchers suggest the trend will continue with snowlines rising hundreds of meters higher by the second half of this century.

California snowlines and lower-elevation ski resorts

In the high Southern Sierra Nevada range, for instance, snowlines are projected to rise by more than 500 meters (1,600 feet) and even more when the mountains get precipitation from atmospheric rivers, jets of water vapor that are becoming an increasingly potent source of the state’s water supply.

“In an average year, the snowpack will be increasingly confined to the peak of winter and to the highest elevations,” the study says.

Diminished snowfall is a consequence of a changing climate in which places like California will get an increasing portion of their winter precipitation as rain instead of snow. The authors said this study and related research suggest water resource managers will need to adapt to a feast-or-famine future. California’s water supply will arrive less through the gradual melt of mountain snowpack that gets the state through hot summers and more via bursts of rain and runoff delivered by atmospheric rivers, which are boosted by warming and are associated with higher snowlines than other storms.

Warmer summers

Such events will further complicate the balancing act between protecting people and infrastructure from winter flooding and ensuring enough water supply during warmer summers.

“This work adds insight into the climate change narrative of more rain and less snow,” said California Department of Water Resources Climatologist Mike Anderson. “DWR appreciates our partnership with Scripps to help water managers develop, refine, and implement adaptation efforts as the world continues to warm and climate change impacts are realized.”

The study, funded by the U.S. Bureau of Reclamation and the DWR, appears in the journal Climate Dynamics today.

“This is the longest and most detailed account of snow accumulation in California,” said Gershunov, “resolving individual storms over 70 years of observed weather combined with projections out to 2100.”

Climate change impacts to ski industry

The authors make note of what this could mean for ski resorts around the state if climate change progresses unabated. For example, Mammoth Mountain, at an elevation between 2,400 and 3,300 meters (7,900 – 11,000 feet), is projected to receive 28 percent less snowfall in the latter half of the century. Lower elevation ski resorts such as Palisades and Northstar, both near Lake Tahoe, span elevational ranges of around 1,900 and 2,700 meters (6,200 – 8,900 feet). They are projected to lose more than 70 percent of their snow accumulation in an average winter.

“Snowlines will keep lifting”

“Observations and future climate projections show that already rising snowlines will keep lifting,” said Gershunov. “Epic winters will still be possible, though, and unprecedented snowfalls will ironically become more likely due to wetter atmospheric rivers, but they will be increasingly confined to the peak of winter and to the highest elevations of the Southern Sierra Nevada.”

Study co-authors include Kristen Guirguis, Daniel Cayan, David Pierce, Michael Dettinger, and F. Martin Ralph of Scripps Oceanography, Benjamin Hatchett of the Desert Research Institute of Reno, Nev., Aneesh Subramanian of University of Colorado at Boulder, Steven Margulis and Yiwen Fang of UCLA, and Michael L. Anderson of the California Department of Water Resources.

(Editor’s Note: Story by Robert Monroe, at UC San Diego Scripps Institution of Oceanography. The San Diego County Water Authority has partnered with the Scripps Institution of Oceanography at UC San Diego to better predict atmospheric rivers and improve water management before, during, and after those seasonal storms.)

California Snowlines On Track To Be 1,600 Feet Higher by Century’s End

This winter produced record snowfall in California, but a new study suggests the state should expect gradually declining snowpacks, even if punctuated with occasional epic snowfalls, in the future.

An analysis by Tamara Shulgina, Alexander Gershunov, and other climate scientists at UC San Diego’s Scripps Institution of Oceanography suggest that in the face of unabated global warming, the snowlines marking where rainfall turns to snow have been rising significantly over the past 70 years. Projections by the researchers suggest the trend will continue with snowlines rising hundreds of meters higher by the second half of this century.

Snowmelt is Swelling Colorado’s Rivers, but Much More Snow is Still Waiting in the High Country

Floods, swollen rivers, road closures — Colorado’s spring runoff season is in full swing and much of the snow in the state’s mountains hasn’t melted yet. Colorado saw higher-than-average snowfall build up on the Western Slope this year, a boon for irrigators and other water users who rely on the Colorado River Basin which spans Colorado, tribal lands, six Western states and parts of Mexico. But the snowmelt, with the help of recent weather, is leading to high runoff and its adverse impacts are popping up around the state like a game of whack-a-mole.

California Agencies Warn of Potential Summer Floods as Lake Levels Climb to Full Capacity

As California agencies brace for possible summer floods, officials are warning visitors of Northern waterways to take precaution as record-breaking snow packs built up from winter storms continue to liquify.

Both Lake Oroville and Lake Shasta reported near-full capacity Monday.

Higher Food Bills? Your Veggies, Nuts and Berries May Cost More Thanks to Extreme Weather

Snow, torrential rains, massive floods. Extreme weather has battered the U.S. this year, and shoppers likely will feel the lingering effects at the grocery store heading into summer.

Reborn From Record Winter, Tulare Lake Could See Explosive Growth From Snowmelt

Tulare Lake has sprung back to life, its shoreline rapidly expanding from the runoff of a winter of epic rainstorms and the melting of the massive southern Sierra snowpack.

The lake, which has been mostly dry for decades, now covers miles of rich farmland and is threatening to overwhelm nearby communities.

Snow Surveys Help Plan Snowmelt Runoff Forecasts

The California Department of Water Resources May 1 conducted the fifth snow survey of the season at Phillips Station. The manual survey recorded 59 inches of snow depth and a snow water equivalent of 30 inches, which is 241% of average for this location on May 1.

The last time there was measurable snow at the Phillips snow course on May 1 was 2020, when only 1.5 inches of snow and .5 inches of snow water equivalent was measured.

DWR’s electronic readings from 130 snow sensors placed throughout the state indicate the statewide snowpack’s snow water equivalent is 49.2 inches, or 254% of average for May 1.

The snow water equivalent measures the amount of water still contained in the snowpack and is a key component of DWR’s water supply run-off forecast.

‘We’re Not Prepared’: Experts Call for Doubling Levee Protections as California Faces Increasing Floods

California water experts and environmental justice advocates are calling for state leaders to mandate that new levees be built with double the federal required protection to withstand the increasingly severe storms caused, in part, by human-caused climate change.

California’s levee protection regulations are not uniform; the state’s seemingly endless dikes and causeways are overseen by a patchwork of widely varying rules. Some communities like Pajaro in Monterey County, which was swamped by floodwaters this year, are protected only against smaller storms that happen every eight years, while levees protecting urban areas of the Central Valley are bolstered against much more powerful storms.

Hundreds Of Hazardous Sites in California Are At Risk Of Flooding As Sea Level Rises, Study Finds

Hundreds of hazardous industrial sites that dot the California coastline – including oil and gas refineries and sewage-treatment plants – are at risk of severe flooding from rising sea levels if the climate crisis worsens, new research shows.

If planet-warming pollution continues to rise unabated, 129 industrial sites are estimated to be at risk of coastal flooding by 2050 according to the study, published Tuesday in the journal Environmental Science & Technology by researchers from University of California at Los Angeles and Berkeley, as well as Climate Central.

Snow Surveys-DWR-Snowmelt-Flooding-May 1

Snow Surveys Help Plan Snowmelt Runoff Forecasts

The California Department of Water Resources May 1 conducted the fifth snow survey of the season at Phillips Station. The manual survey recorded 59 inches of snow depth and a snow water equivalent of 30 inches, which is 241% of average for this location on May 1. The last time there was measurable snow at the Phillips snow course on May 1 was 2020, when only 1.5 inches of snow and .5 inches of snow water equivalent was measured

DWR’s electronic readings from 130 snow sensors placed throughout the state indicate the statewide snowpack’s snow water equivalent is 49.2 inches, or 254% of average for May 1.

The snow water equivalent measures the amount of water still contained in the snowpack and is a key component of DWR’s water supply run-off forecast.

“While providing a significant boost to California’s water supplies, this year’s massive snowpack is posing continued flood risks in the San Joaquin Valley,” said DWR Director Karla Nemeth. “The snowpack will not disappear in one week or one month but will lead to sustained high flows across the San Joaquin and Tulare Basins over the next several months and this data will help us inform water managers and ultimately help protect communities in these regions.”

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Snowmelt runoff forecasts

Snow surveys like the one at Phillips Station are critical to planning for impacts of the coming snowmelt runoff on communities. DWR uses the most updated technology to gather data from snow surveys, a network of 130 remote snow sensors, and airborne snow observatory data to gather information on current real-world conditions to create the most accurate snowmelt runoff forecasts possible. These runoff forecasts, published through DWR’s Bulletin 120, allow reservoir operators to plan for anticipated inflows and water managers downstream of reservoirs to plan and prepare for flood risks.

Despite a brief increase in temperatures in late April, the statewide snowpack overall melted at a slower pace than average over the month of April due to below average temperatures early in the month and increased cloud cover. An average of 12 inches of the snowpack’s snow water equivalent has melted in the past month and it now contains an average of 49.2 inches.

Water supply, flood control planning

“No matter how you look at the data, only a handful of years in the historical record compared to this year’s results,” said Sean de Guzman, manager of DWR’s Snow Surveys and Water Supply Forecasting Unit. “Survey results from our partners in the California Cooperative Snow Surveys Program and other data, including data from Airborne Snow Observatory flights, allow us to incorporate these data into our models to provide the most accurate snowmelt runoff forecasts possible right now to inform water supply, flood control, and planning.”

Climate Change and snowpack averages

According to historical records, only the April 1 measurements from the years 1952, 1969, 1983 and this year were above 200 percent, although it is difficult to directly compare individual years across the decades due to changes in the number of snow courses measured over time.

Due to the impact of climate change on California’s snowpack, since 2021, snowpack averages have been calculated using a timeframe of 1991 through 2020 so that results better reflect the current climate conditions.

DWR is maximizing the amount of water that can be stored and diverted from this record snowpack.

In April, DWR announced a 100% allocation of requested supplies from the State Water Project, which delivers water to 29 public water agencies that serve 27 million Californians and 750,000 acres of farmland. The last time the SWP allocated 100% was in 2006. DWR is also maximizing the amount of water that can be diverted towards recharging groundwater basins so more water is stored for future use in underground reservoirs.

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Flooding impacts in California

Last week, Governor Newsom visited the Tulare Basin to tour flood impacts first hand, met with community leaders and emphasized the state’s commitment to supporting and providing appropriate assistance to counties impacted by recent and anticipated flooding this spring and summer.

Snowmelt runoff forecasts are an instrumental part of the assistance provided by DWR’s State-Federal Flood Operations Center (FOC), which is supporting emergency response in the Tulare Lake Basin and Lower San Joaquin River by providing technical and materials assistance to support ongoing flood response activities.

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 more than 1.4 million sandbags, 1 million square feet of plastic sheeting, and 9,000 feet of reinforcing muscle wall, across the state since January.

(Editor’s  Note: Information in this story was provided by the California Department of Water Resources).