Our recent wet trend has brought a boost to our state’s water supply, and we may be heading into another stretch of wet weather in February. So how are our reservoirs doing?
Across the western U.S., many areas received record or near-record amounts of snowpack over the winter. With the spring and summer temperatures melting the abundant snow, a record volume of streamflow has been recorded in several basins in the southwestern U.S., providing more water for the area later into the summer than is typically seen.
The Walker and Carson basins near the California-Nevada border, for example, have reported the largest volume of streamflow for April through July that has ever been observed in roughly a century, when the records began. The ample runoff is helping fill reservoirs that have been depleted from years of drought conditions.
Dry conditions dominated the West and southern Plains, coupled with above-normal temperatures. Precipitation was most widespread throughout much of the upper Midwest and central Plains and into the Northeast. Almost the entire country had near- to above-normal temperatures this last week, with the greatest departures over the Southwest and central Plains where temperatures were at least 4-7 degrees above normal.
Cooler-than-normal temperatures were recorded in the Pacific Northwest with departures of 3-6 degrees below normal. At the end of the current U.S. Drought Monitor period, significant rains developed over portions of the Midwest and central Plains, and they will be accounted for in the next analysis.
July 2023 recorded more than 6,500 severe weather reports, the most preliminary July reports on record, according to our friends at the @NWSSPC. As we head into August, where is severe weather most likely this time of year? https://t.co/pySvHxoQQt pic.twitter.com/6C4u82SGYa
— NOAA Climate.gov (@NOAAClimate) August 7, 2023
Central portions of the Intermountain West may be spared degradation, as those areas are still showing residual benefits from above normal winter snowpack leading up to the summer, in addition to periods of above normal rainfall during the last 60 to 90 days. Seasonal temperature and precipitation outlooks, ENSO, and climatology favor widespread drought improvement and removal across the central U.S. However, drought persistence is favored across the Upper Midwest, although there is the potential for localized improvements.” Read full assessment: cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.php.
Colors show where total precipitation has an increased chance of being higher or lower than usual during the next three months. The darker the shading, the greater the chance for the indicated condition. White areas have equal chances for precipitation totals that are below, near, or above the long-term average (median) for the next three months.
Climate scientists base future climate outlooks on current patterns in the ocean and atmosphere. They examine projections from climate and weather models and consider recent trends. They also check historical records to see how much precipitation fell when patterns were similar in the past.
🌡️📈#ERA5 data from the #CopernicusClimate Change Service show that July 2023 was the hottest month on record globally.
Check the data 👉 https://t.co/Ug5FznAlMW pic.twitter.com/jnsJWOT53Z
— Copernicus ECMWF (@CopernicusECMWF) August 8, 2023
Record-high temps & devastating floods struck the U.S. 15 separate billion-dollar disasters occurred during the 1st 7 months of 2023. More from NOAA’s July State of Climate report.
El Niño is anticipated to continue through the Northern Hemisphere winter (with a greater than 95% chance through December 2023-February 2024). An #ElNino Advisory remains in effect. https://t.co/5zlzaZ1aZx pic.twitter.com/j5Kb91Uoty
— NWS Climate Prediction Center (@NWSCPC) August 10, 2023
(Editor’s Note: Content for this story comes from the Natural Resources Conservation Service, which produces a weekly report using data and products from the National Water and Climate Center and other agencies. The report focuses on seasonal snowpack, precipitation, temperature, and drought conditions in the United States.)
A winter of record snowfall in California, coupled with a triple-digit heat wave, is continuing to inundate Sierra trails and fill valley reservoirs with snowmelt run-off.
In a video posted on social media by a KCRA 3 viewer, ankle-deep water could be seen rushing over the rail to Wapama Falls in Yosemite National Park last week.
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.
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.
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.
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.”
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.
“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… pic.twitter.com/zIOiGMm0I7
— CA – DWR (@CA_DWR) May 1, 2023
“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.”
@CA_DWR uses data from the 5/1 snow survey as well as ASO aircraft-based LiDAR & remote snow sensors to forecast & supply current conditions of the snowpack in real-time & provide water managers, #flood agencies & emergency responders the most accurate snowmelt forecasts possible pic.twitter.com/dsuRxt1ORJ
— CA – DWR (@CA_DWR) May 1, 2023
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.
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.
May Drought Outlook by @NOAA’s @NWSCPC
Some potential improvement in the drought-stricken Southern Plains. Also the East, Gulf Coast, and a bit of CA/NV.
Drought may develop on the Eastern Plains and Midwest including part of KS, NE, IA, MO, and IL.
Otherwise, drought persists pic.twitter.com/OfVbjzpMbh
— NIDIS Drought.gov (@DroughtGov) May 1, 2023
(Editor’s Note: Information in this story was provided by the California Department of Water Resources).
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.
The California Department of Water Resources announced Monday that it slowed outflows from Lake Oroville from 35,000 cubic feet per second to 27,500 cfs.
According to a press release issued Monday by DWR, the reduction began at 6 p.m. Monday.
For decades, Californians have depended on the reliable appearance of spring and summer snowmelt to provide nearly a third of the state’s supply of water. But as the state gets drier, and as wildfires climb to ever-higher elevations, that precious snow is melting faster and earlier than in years past — even in the middle of winter.
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