As temperatures are expected to rise this week, Sierra Nevada snowpack is at risk of melting at an accelerated rate, potentially increasing the chances of flooding in the Central Valley and other regions. The melting period is upon us, and while there are no flood risks for the most communities of Northern California, temperatures could reach up to 90 degrees in certain areas.
The National Weather Service issued a flood watch from Thursday through Tuesday for the Merced River in Yosemite National Park, with predictions that the river will exceed its 10-foot flood stage by 1 to 2 feet by the weekend. This could lead to moderate flooding on the main roads in and out of Yosemite Valley, possibly resulting in the park’s temporary closure. Yosemite is expected to close intermittently from late April to July due to the snowpack’s impact on waterfalls, rivers, and streams.
The most significant flood risk, however, is concentrated in the Tulare Basin in southern San Joaquin Valley. At least 60,000 acres of farmland in Kings County and Tulare County are submerged under approximately three feet of water due to heavy rains from atmospheric river storms in mid-March. Farmers and residents in the area, including those in Corcoran, are concerned about the impact of the warming weather on the temporarily repaired levees.
Officials have expressed concern about the potential failure of these levees during the hot weather. While there is enough room in reservoirs to capture excess water, the risk of flooding is expected to increase into May as temperatures continue to rise. The Tulare Lake Basin’s geography further complicates the situation, as it sits in a large bowl with no quick drainage options due to its history and groundwater overpumping by farmers.
The statewide Sierra snowpack is at 256% of average, while the Southern Sierra, which experienced a record-breaking winter, is at 322%. State Office of Emergency Services officials have been collaborating with local authorities in the Tulare Lake Basin for the past month in preparation for potential flooding.