Drought — Carquinez Strait and Delta, California

2021-11-01 to 2021-11-30 · Carquinez Strait and Delta, California

Event narrative

For the month of November, the U.S. Drought Monitor improved portions of Zone 18 to extreme drought (D3) with the southeastern portion of the zone remaining in exceptional drought (D4). The zone continued to see much of the same impacts already affecting the region, however, there are some signs of improvement. They continue to mention impacts to: agriculture, water supplies, recreation, and ecosystems. By November it was reported that an estimated 2.6% of endangered juvenile winter-run Chinook salmon survived the season leading to concern about the future of the species. The temporary rock wall in the Delta remains in place until further notice that was originally expected to be dismantled in November. Drought conditions may continue to improve as we continue into the rainy season that started October 1st.

Wider weather episode

Northern California typically experiences a wet season, October through May, and a dry season May through September. Last year's water year, October 2019 through September 2020, was one of the driest on records. This likely contributed to the U.S. Drought Monitor's decision to place portions of interior northern California into extreme drought on September 29, 2020. Portions of Shasta, Tehama, Butte, Glenn, Colusa, Yolo, Solano, Yuba, Nevada, and Sacramento counties remain in extreme drought. The rest of interior northern California was placed into severe drought (D2) on December 8; however, the state of California has not announced that these locations are in drought. On 4/21/2021 the Biden-Harris administration announced the formation of an Interagency Working Group to address worsening drought conditions in the West. On 5/10/2021 Governor Gavin Newsom significantly expanded his April 21 drought emergency proclamation to include Klamath River, Sacramento-San Joaquin Delta and Tulare Lake Watershed counties where accelerated action is needed to protect public health, safety and the environment. In total, 41 counties are now under a drought state of emergency, representing 30 percent of the state's population. By late June more wildlife was observed in urban interfaces than normal, notably bears and rattlesnakes, in search of wetter, cooler conditions. Widespread water theft has also been reported. On July 8th, the Governor of California asked for all Californian's including businesses, to voluntarily reduce water usage by 15%. On August 10th DWR reported the drought has led to a 123% increase in the number of acres burned this year, compared to 2020. DWR also reported that the low reservoir water levels have also affected energy supplies, agriculture, communities and state recreation parks. By October, Glenn County received 210 reports of well related incidents. Of the 210 reports, 148 selected the dry well designation. An estimated 2.6% of endangered juvenile winter-run Chinook salmon survived the season. In the month of October, some improvement was made to the drought condition further improving by the end of November. However, drought conditions continue across interior northern California.

Source: NOAA Storm Events Database, event_id 993145. Narrative written by the NWS forecast office that issued the report.