La Niña, the cooling of the equatorial Pacific that shifts weather patterns the world over, is fading away. But California may still be prone to dryness, and the U.S. Gulf Coast faces the risk of another busy hurricane season. Water temperatures in the Pacific Ocean will likely return to normal in the next few months, the U.S. Climate Prediction Center said in a report Thursday.
Dry conditions in the Southwest, largely associated with La Niña, have intensified what the National Oceanic and Atmospheric Administration is calling the most significant U.S. spring drought since 2013, affecting an estimated 74 million people.
The winter storms that dumped heavy snow and rain across California early in 2021 are likely not enough to negate what will be a critically dry year, state water officials believe.
California’s Department of Water Resources on Tuesday recorded a snow depth of 56 inches and water content of 21 inches at Phillips Station in the Sierra Nevada. The water content of the overall snowpack was 61% of the average for March 2 and 54% of the average for April 1, when it is historically at its maximum.
A Scripps Center for Western Weather and Water Extremes report shows that more atmospheric rivers have made landfall over the U.S. West Coast in the first four months of Water Year 2021 compared to the previous period in 2020.
There’s a race on in California, and each day matters: the precipitation during winter that fuels the snowpack in the Sierra Nevada and fills groundwater supplies has been slow to start, and faltering at best. Northern California remains stuck in one of the worst two-year rainfall deficits seen since the 1849 Gold Rush, increasing the risk of water restrictions and potentially setting up dangerous wildfire conditions next summer.
How is California’s snowpack measured? Why is it important? And how is our snowpack stacking up this winter, so far? NBC 7 meteorologist Crystal Egger breaks it all down.
Precipitation is below average in California for the current water year. Despite recent storms that increased the statewide Sierra Nevada snowpack to 70% of average to date, the state is experiencing its second consecutive below average year for rain and snow. The water year starts on October 1 and ends September 30.
The Department of Water Resources Feb. 3 conducted the second manual snow survey of the season at Phillips Station. The manual survey recorded 63 inches of snow depth and a snow water equivalent, or SWE, of 17 inches, which is 93% of average for that location, according to the DWR. The SWE measures the amount of water contained in the snowpack and is a key component of DWR’s water supply forecast.
“The recent blast of winter weather was a welcome sight, but it was not enough to offset this winter’s dry start,” said DWR Director Karla Nemeth. “While there is still a chance we will see additional storms in the coming weeks, the Department and other state agencies are preparing for the potential for a second consecutive year of dry conditions.”
Below normal precipitation is favored throughout most of the southern tier of the United States in late February to early March, according to the National Weather Service Climate Prediction Center. La Niña conditions remain over the Pacific Ocean.
Statewide snow survey measurements reflect those dry conditions. Measurements from DWR’s electronic snow survey stations indicate that statewide the snowpack’s SWE is 12.5 inches, or 70% of the February 3 average, and 45% of the April 1 average. April 1 is typically when California’s snowpack is the deepest and has the highest SWE.
“The recent atmospheric storms have brought rain and snow to the northern Sierra Nevada, but conditions are still well below normal,” said Goldy Herbon, San Diego County Water Authority senior resources specialist.
Following last year’s below average water year, northern California is now experiencing its second straight water year of below average precipitation.
How it started.
How it's going.Season-to-date snowfall through January 23 vs February 4.#CAwx #CAsnow ❄️☃️🏂🌨️ pic.twitter.com/UOvjEmxa5k
— NWS Sacramento (@NWSSacramento) February 4, 2021
Another source of the state’s water supply, the Colorado River Basin, isn’t faring much better. The water year 2021 precipitation at the end of January for the Colorado River Basin is 66% of normal, according to the U.S. Bureau of Reclamation.
Precipitation totals to date are behind historical averages for two of the main sources of San Diego County’s supply, with two months to go in the winter season but, a couple of atmospheric rivers can change that quickly.
“The San Diego region will have a plentiful and reliable source of water due to actions taken by the Water Authority and its 24 member agencies to diversify the water supply,” said Herbon. “Continuing efforts to expand supply sources, including desalination, water reuse, and recycling, will ensure that the water needs are met for the region’s 3.3 million people and its $245 billion economy.”
Fall 2020 was extremely dry, especially in the Sierra Nevada, and follows last year’s below-average snow and precipitation, according to the DWR. With only a couple months remaining in California’s traditional wet season, DWR officials say Californians should look at ways to reduce water use at home.
Statewide Sierra Nevada snowpack is 71% of average for February 4, 2021. Graphic: California Department of Water Resources
We had a very late start to the rainy season this year, similar to what we have seen in recent years. We’ve seen about one-third of the normal rainfall for the current date—well below the normal amount. There could be a weather pattern explaining some of the lack of rain. That is called a La Niña weather pattern.
Earth’s rising fever hit or neared record hot temperature levels in 2020, global weather groups reported Thursday.
While NASA and a couple of other measurement groups said 2020 passed or essentially tied 2016 as the hottest year on record, more agencies, including the National Oceanic Atmospheric Administration, said last year came in a close second or third. The differences in rankings mostly turned on how scientists accounted for data gaps in the Arctic, which is warming faster than the rest of the globe.
Global warming pushed temperatures into record territory in 2020, in effect tying 2016 as the hottest year on record, according to data released Thursday by U.S. science agencies.
Last year’s average global surface temperature was 2.2 degrees Fahrenheit above the late 19th century average, according to NASA. It was the fifth consecutive year of more than 2 degrees above that base line. Indeed, the seven hottest years in 140 years of record keeping are the last seven. In descending record order, they are 2020 and 2016, 2019, 2017, 2015, 2018 and 2014.
The Water News Network is San Diego County’s source for water news and information.
