The INSASE Disparity in Precipitation Between Northern California and Southern California
The start of California’s rainy season has brought a stark contrast in weather patterns across the state.
While Northern California has been drenched with storms, Southern California remains bone-dry, creating a disparity that experts suggest could be unprecedented and leading to the worst wildfires in Los Angeles’s history.
Since July, Los Angeles has recorded just 0.2 inches of rain, its second-driest start to the rainy season in nearly 150 years. Meanwhile, Northern California has experienced weeks of heavy rainfall, flooding, and even tornadoes.
Santa Rosa, for example, has received nearly double its average rainfall, with 7 inches falling in a single day in November—a record-breaking deluge.
“There have been few if any years since 1895…that have been so much above-normal in the northern part of the state while simultaneously so dry in the south,” Daniel Swain, a UCLA climate scientist, wrote on Weather West.
Southern California’s parched landscape, combined with fierce Santa Ana winds, has turned vegetation into tinder, sparking fast-moving wildfires like the Palisades Fire. These dry conditions, coupled with relentless winds, have made containment efforts exceedingly difficult. The lack of rainfall is not only prolonging fire season but intensifying its impact, forcing evacuations and destroying homes.
Despite Southern California’s dry conditions, water supplies remain stable thanks to abundant rainfall in Northern California, which feeds the state’s major reservoirs.
Lake Oroville and Lake Shasta, two of California’s largest reservoirs, are well above average for this time of year, at 128% and 130% of capacity, respectively. Snowpack levels in the northern Sierra Nevada are also promising at 150% of normal.
Experts warn that California’s weather extremes—wet winters and dry summers—are intensifying due to climate change. As Governor Gavin Newsom stated, the state is facing “simultaneous droughts and rain bombs,” another example of the urgency for innovative water management strategies to adapt to a shifting climate.
