Snow that falls on the Sierra Nevada mountain range each winter ends up being a natural tank that slowly melts and flows down into the river valleys in spring and summer season. In a normal year, this snowpack represent approximately 30% of Californias supply of water. Resource supervisors depend on this snowmelt to replenish tanks with sufficient water for the generally dry months of summer and fall.
” This previous winter was one of extremes within an overall downward trend,” Molotch kept in mind. “These are natural occasions that might generally occur, however worldwide warming has amplified whatever. The trajectory of climate change has put us on a course where the regular wild swings of winter season are now warp-drive wild.”
The see-saw pattern of rain and snowfall along the western coast of North America is sometimes linked to El Niño and La Niña patterns– which modify climatic flow in the tropics and mid-latitudes– and to the atmospheric rivers that occasionally funnel bursts of moisture towards California from the tropical Pacific. The past couple of years have actually brought consistent La Niña conditions in the tropical Pacific that tend to make some areas drier. At the same time, ever-warming international temperature levels and changing jet streams have actually brought more frequent clear and dry weather to the mountains.
The result is a significantly reduced snowpack in 2022 The deficit is apparent in the snow water equivalent (SWE) for the Sierra Nevada, a measurement of how much water you would get if all of the snow in a given location melted at the same time. According to the California Department of Water Resources (CA-DWR), Sierra Nevada SWE on April 1 stood at simply 37 percent of the long-term average.
October 1, 2021– May 3, 2022
The snow water equivalent on December 30 was calculated by CA-DWR to be 160 percent of normal. By May 5, 2022, CA-DWR reported Sierra-wide snow water equivalents were back down to 27 percent of typical.
The line chart above shows the boom-and-bust pattern as observed at Donner Pass, site of the Central Sierra Snow Lab (CSS Lab), one of the oldest snow-measurement operations in the mountain range. The peak snow water comparable throughout the 39-year record (rushed line) normally happens around March 24, with a median at 37.2 inches. In 2022, SWE peaked at 27.6 inches on January 12 and started falling on February 6. The data in the chart come from the SNOTEL network, which is managed by the U.S. Department of Agriculture. In California, several water, research, and power organizations track the ebb and circulation of mountain snow.
Natural-color satellite images (listed below) can broadly show the progress of the snow season and help researchers evaluate the level of snow cover. However they provide little about snow depth. And while SNOTEL and other monitoring networks offer a few of the longest day-to-day records of snow depths and water material over the previous 4 years, the measurements come from specific areas and mainly within a narrow elevation range.
November 3, 2021– May 4, 2022.
To fill out the spaces in what we understand about snow water at greater elevations and throughout larger geographic locations, scientists have been establishing tools to theorize and insert the snowpack. The map at the top of this page is one such effort.
Based on information supplied by Molotch and INSTAAR colleagues Leanne Lestak and Kehan Yang, the experimental product illustrates snow water equivalents on April 24, 2022, and how they compare to the long-lasting average for the mountain variety. The quotes of SWE are originated from a mix of 20 years of NASA satellite data, the SNOTEL record, topographic info, and computer modeling. Seed funding for the product was originally supplied by NASAs applied sciences program, and it is now supported by CA-DWR.
As of INSTAARs April 24 report, the percent of average SWE above 5,000 feet elevation was highest in the main region of the Sierra Nevada (61 percent), then the north (47 percent), and least expensive in the south (41 percent). Just one week later on, those numbers dropped to 42 percent in the main Sierra, 33 percent in the south, and 26 percent in the north.
” Our natural water tower is becoming leaky,” stated Benjamin Hatchett, a hydroclimatologist at the Desert Research Institute who studies snow droughts. “If snow is melting earlier, that suggests water is coming out of our natural mountain reservoir earlier. This also implies we need to manage it downstream when we might not have the versatility that we would like.”
“Warming and drying will lead to more snow-free days, and snow will begin melting out earlier. As this meteorology continues to move, how will the groundwater and the surface hydrology react to the low snow conditions, the particular extreme years, and the back-to-back dry years?
NASA Earth Observatory images by Joshua Stevens and Lauren Dauphin, using data thanks to Leanne Lestak/University of Colorado-INSTAAR, the USDA Natural Resources Conservation Service, and MODIS information from NASA EOSDIS LANCE and GIBS/Worldview.
The deficit is obvious in the snow water equivalent (SWE) for the Sierra Nevada, a measurement of how much water you would get if all of the snow in a given location melted at once. The snow water equivalent on December 30 was determined by CA-DWR to be 160 percent of regular. By May 5, 2022, CA-DWR reported Sierra-wide snow water equivalents were back down to 27 percent of regular.
Natural-color satellite images (below) can broadly reveal the progress of the snow season and aid scientists evaluate the degree of snow cover. Based on information provided by Molotch and INSTAAR associates Leanne Lestak and Kehan Yang, the experimental item illustrates snow water equivalents on April 24, 2022, and how they compare to the long-term average for the mountain range.
April 24, 2022
The California range of mountains alternated between severe rainfall and none at all this winter season.
When it concerns mountain snow, the Sierra Nevada is notorious for busts and booms: One year can be extremely bad, while the next can be exceedingly great. Nevertheless, in 2021-22, there were booms and busts all within the same snow season. The outcome has been another year of insufficient snowfall, raising concerns about the effect on water materials.
” The Sierras tend to get big storms, with a great deal of snow in bursts, or we get years of very little snow,” said Noah Molotch, a mountain hydrologist at the Institute of Arctic and Alpine Research (INSTAAR) and NASAs Jet Propulsion Laboratory (JPL). “It is unusual that we have a snow year that is really typical.”