As California’s water supply is steadily dwindling, it is piling up warm weather records at a feverish pace. Disturbingly, the weather pattern responsible for this hot, dry pattern shows no signs of relenting as scientists gain more clues into what’s causing it.
In a must-read Op-Ed published in the LA Times last Thursday, NASA’s Jay Famiglietti called for immediate water rationing in laying out several depressing facts about the state of water affairs in California, due to the drought:
- Groundwater and snowpack levels are at all-time lows
- Water stored in the Sacramento and San Joaquin river basins was 34 million acre-feet below normal in 2014
- It has lost about 12 million acre-feet of total water annually since 2011
- It has about one year of water supply remaining in its reservoirs
As the drought has gotten worse, the heat – which intensifies drought by speeding up evaporation and drying out the land surface – has been a constant.
2014 was California’s hottest year on record. And it just had its warmest winter on record, by a long shot. It was 1.5 degrees warmer than the previous record, set just the winter before (in 2013-2014).
The weather pattern responsible for the heat and drought is a bulging area of high pressure over the West, extending into Alaska, that has blocked rain-bearing weather systems from coming ashore. Dubbed the “ridiculously resilient ridge“, models have forecast its demise on several occasions, only for it come back stronger.
University of Washington professor of atmospheric science Dennis Hartmann, in a guest essay at Climate.gov, says a particular configuration of sea surface temperatures in the tropical Pacific is behind this pattern. He calls it the “North Pacific Mode”, which is characterized by a plume of warmer than normal ocean temperatures from the western tropical Pacific that extends eastward and northward towards the West Coast of North America.
“This pattern brings warmth and drought to the West and cold to the East, as we have observed the past two winters,” Hartmann writes.
Hartmann stops short of attributing this pattern to global warming and notes this kind of pattern has been seen in the past.
However, a study in the Proceedings of the National Academy of Sciences – published earlier this month – finds global warming is increasing the likelihood warm and dry conditions coincide – increasing drought risk, irrespective of the background weather pattern.
Hot and dry now, more to come…
After the record warm winter, the heat has only intensified since the start of March.
Downtown Los Angeles soared to record highs on Friday, Saturday, and Sunday.
— NWS Los Angeles (@NWSLosAngeles) March 14, 2015
— NWS Los Angeles (@NWSLosAngeles) March 15, 2015
— Rob Marciano (@RobMarciano) March 16, 2015
The City of Angels is forecast to hit 90 degrees once again this afternoon, something it has never done in the month of March on four consecutive days. In fact, four 90 degree days in March at any time would be a record, the National Weather Service office serving Los Angeles says. Its average temperature so far this month is nearly 7 degrees above average.
[Update, 2 p.m. Tuesday: Los Angeles indeed hit 90 on Monday for the 4th consecutive day for the first time on record in March]
The outlook for precipitation in Southern California and across the state is also grim. Drought conditions – currently afflicting 99.8 percent of the state – are predicted to persist or intensify through the spring.
And recently, climate studies have warned of an increased risk of megadroughts – severely dry conditions that sometimes last for decades.
NASA’s Famiglietti calls for a coordinated plan focused on addressing the long-term nature of the crisis. “Call me old-fashioned, but I’d like to live in a state that has a paddle so that it might also still have a creek,” he concludes.