File:Recent Storms in the Sierra Nevada Eases Fear of Snow Drought (MODIS 2024-02-26).jpg

English: February 11, 2024 January 29, 2024

Sierra Nevada is a Spanish name that means “snowy mountain range.” While the term “snowy” has held true for most years, the beginning of the 2023-2024 was far below average, bringing concerns about a severe snow drought in the making. Given that roughly 30 percent of California’s water needs depend on the snowpack that fills these mountains, a significant lack of snow would have far-reaching implications for agriculture, industry, recreation, human health, and the environment.

According to the California Department of Water Resources (CDWR), the snowpack was at only 28 per cent of average on January 1, 2024. Warm temperatures in December and early January meant that precipitation had fallen primarily as rain even in higher elevations. By January 30, CDWR reported a modest gain in snowpack, which was reported as 52 percent of average for that date.

Fortunately, cooler temperatures and a series of precipitation-laden atmospheric rivers in February has given the Sierra snowpack a much-needed boost. As of February 23, the CDWR estimated statewide snowpack at 85 percent of normal for the date, and 70 percent of the April 1 average. The report also offered the breakdown for percentage of normal for the date for different sections of the Sierra Nevada: Northern Sierra was 98 percent; Central Sierra was 81 percent; Southern Sierra was reported at 78 percent.

Although many local and national media outlets published enthusiastic articles, some touting the end to the snow drought, the U.S. Drought Monitor provided a more measured assessment. On February 15 they advised, “…atmospheric river events alleviated water year precipitation deficits throughout parts of the region. The February 4-7 event brought 20 percent to over 40 percent of water year normal precipitation for parts of southern California. Snow drought conditions are improving, but the Sierra Nevada snowpack remains below normal.”

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired two true-color images that show the dramatic change in the Sierra Nevada snowpack in just a matter of a few weeks. The first, acquired on February 11, 2024, shows abundant snow across not only high elevations in California, but also draped across much of Nevada. The second image, acquired on January 29, 2024, reveals much duller snow (strongly suggestive of thinner snowpack) that clings only to parts of the high Sierra. The two images can be easily compared by tapping on the dates.