Rain is finally coming to San Benito County. But even though December’s rainfall has slightly exceeded the normal amount for the month, it is not yet enough to lift the area out of the drought.
As of Dec. 29, the county has seen 2.41 inches of rain for the month, according to the National Weather Service. Normal precipitation in the county for December is 2.27 inches.
However, we have had 9.1 inches of rain so far this year, just two-thirds of the 13.44 inches considered normal.
Until showers returned on Dec. 14, the lack of rain closely paralleled 1989, the worst year in recent records, when the county received only 6.87 inches of rain. Up until the mid-December rain, the 2021 and 1989 precipitation measurements were identical at 6.85 inches for the year.
This year, according to the U.S. Drought Monitor (USDM), 79% of California is in Extreme Drought, while 23% is in Exceptional Drought—the two most severe categories.
The USDM ranks droughts and their effects on a five-point scale.
- D0 – Abnormally Dry: Soil is dry; irrigation delivery begins early; dryland crop germination is stunted; active fire season begins.
- D1 – Moderate Drought: Dryland pasture growth is stunted; producers give supplemental feed to cattle; landscaping and gardens need irrigation earlier; wildlife patterns begin to change; stock ponds and creeks are lower than usual.
- D2 – Severe Drought: Grazing land is inadequate; fire season is longer, with high burn intensity, dry fuels, and large fire spatial extent; trees are stressed; plants increase reproductive mechanisms; wildlife diseases increase.
- D3 – Extreme Drought: Livestock need expensive supplemental feed; cattle and horses are sold; little pasture remains; fruit trees bud early; producers begin irrigating in the winter; fire season lasts year-round; fires occur in typically wet parts of the state; burn bans are implemented; water is inadequate for agriculture, wildlife, and urban needs; reservoirs are extremely low; hydropower is restricted.
- D4 – Exceptional Drought: Fields are left fallow; orchards are removed; vegetable yields are low; the honey harvest is small; fire season is very costly; the number of fires and area burned are extensive; fish rescue and relocation begins; pine beetle infestation occurs; forest mortality is high; wetlands dry up; survival of native plants and animals is low; fewer wildflowers bloom; wildlife death is widespread; algae blooms appear.
All of San Benito County is considered to be in Extreme Drought, with 5.57% of the area falling into the Exceptional Drought category. In 127 years of tracking rainfall, 2021 is the county’s 32nd driest year to date.
San Luis Reservoir, an important source for San Benito County’s drinking and agricultural water, is also at a historic low. The water level currently stands at 409.8 feet mean sea level (MSL), down significantly from the five-year average of 481.5 feet. At this point last year, the reservoir level was 447.8 feet MSL.
There is optimism over the recent heavy snowfall in the mountains, which will feed the reservoir as it melts. UC-Berkeley’s Central Sierra Snow Lab reports that Donner Pass, for example, currently has 256 inches of snow, with one seven-day storm alone bringing in 117.9 inches. This is far above the normal 99 inches of snowfall at the pass at this point in the year.