Dramatic rainstorms earlier this month brought more than 6in of rain to the California mountains – a full month’s worth of rain in little more than a day – but the deluge wasn’t enough to reverse a worsening drought trend that is set to intensify further in the coming weeks and months.
Just weeks earlier flames leveled hundreds of oceanside homes, a Los Angeles firefighter was washed out to sea, and later rescued.
Massive debris flows transported a thick layer of mud into neighborhoods near Altadena, the same place where search and rescue crews had gone house to house searching for survivors among the wreckage of the worst wildfire disaster in the history of southern California. The hardest hit from the mudslides was the foothills town of Sierra Madre, which was under evacuation orders last month from the Eaton fire – and now must dig out from a newly deposited feet-thick layer of muck.
Such “weather whiplash” – a telltale sign of the climate crisis – looks to shift the semi-arid south-western corner of the US back toward drought as the month of March approaches.
What had been the driest start to a rainy season in history for most of southern California is now looking to return to a weeks-long dry pattern.
Mountain snows during the winter months are crucially important to the healthy flow of the Colorado during the spring and summer months, and this year, they haven’t come. The snowpack across the multi-state region currently sits at just 25% of normal. Annual snowpack in the region typically peaks around 1 March before the spring melt season begins.
With the south-west under the influence of a La Niña weather pattern, which typically results in drier winters across the southern United States, that means time is running out for the approximately 40 million people who depend on water from the Colorado River.
“We are near a tipping point on the Colorado,” said Greg Pierce, an urban planner who directs the UCLA Water Resources Group.
This year’s drought on the Colorado River isn’t new: the current episode of unusual dryness began in 2000, according to data from the US Geological Survey, and has been worsened by the rising temperatures associated with increasing global greenhouse gas emissions.
Over the past month extreme drought – the third-highest scale – has expanded in California, Arizona, New Mexico, Utah and Nevada, according to the US Drought Monitor.
Las Vegas has received less than a quarter of normal rainfall during its wintertime peak. This month’s rains ended a 214-day stretch without any precipitation there.
The Phoenix area received less than 5% of normal rains since last summer, and missed a 50-year dry spell record by a single day. Impacts on farmers and ranchers across Arizona have been severe.
In Los Angeles, extreme drought remains even after the ample recent rains.
While most of southern California has received less than half its normal rainfall, northern California’s reservoirs are full, and February brought nearly 3ft of additional snowpack for the high peaks of the Sierras. Given increasing hydrological inequity across the south-west US, there’s no certainty how long that water will last.