Heat waves. Severe drought. Extreme forest fires.
As Southern California braces for the constraints of an unprecedented drought, long-range forecasts are predicting a summer filled with record temperatures, arid landscapes and potential wildfires, particularly in the northern part of the state.
“The dice are loaded toward huge fires across the West,” said Park Williams, a climate scientist at UCLA. “And the reason is simple: The vast majority of the western part of the country is going through a pretty severe drought.”
Recently, the National Oceanic and Atmospheric Administration said the temperature outlook for this year’s spring-to-summer transition calls for above-normal readings across most of the West.
At the same time, the agency also reported that while long-term forecasts had suggested that the weather phenomenon known as La Niña was dissipating – raising hopes that California could experience a normal winter in 2022 – now it seemed that the “girl” was going strong possibly into a third year.
If NOAA is correct, high temperatures and a persistent La Niña will have significant impacts on water use in urban and agricultural areas across the western US, as well as in the increasingly extreme California fire season.
The federal government has already announced that it will delay water releases from Lake Powell, the nation’s second-largest reservoir, as a result of worsening drought conditions along the Colorado River. In an effort to augment the shrinking reservoir, the U.S. Bureau of Reclamation said Tuesday it plans to retain the water to reduce the risk of the lake falling below a point where the Glen Canyon Dam stops generating electricity. .
Unlike its more familiar and wetter sibling, El Niño, La Niña typically brings dry winters to Southern California and the Southwest.
Now, with California’s rainy season in the rearview mirror and a hot, dry summer fast approaching, forecasters say La Niña has a 59% chance of continuing through the summer, and up to a 55% chance of persisting through the summer. fall.
NOAA’s seasonal outlook predicts a hot summer in the West.
(Paul Duginski / Los Angeles Times)
Experts say this summer could be a repeat of last year, when fires burned more than 2.5 million acres across California — more than any year except 2020.
“Last year, one thing that made fire season especially active was the extreme heat waves that occurred throughout the West during the summer,” Williams said. “So we are in a similar situation this year, where we are going to go into the summer with extremely dry conditions. What we don’t know yet is whether there are going to be more record heat waves this year. That is why there is still a lot of uncertainty about how the fire season will unfold.”
Global warming due to human activity has increased the likelihood of severe heat waves, and higher temperatures also worsen drought by causing snow cover to melt faster and more precipitation to fall as rain instead of snow.
“The odds of record heat waves this year are higher than normal,” says Williams. “But there is still room for hope that we will have some luck.”
Already this year, California has seen 1,402 fires that have collectively burned 6,507 acres. That compares with 1,639 fires that burned 4,779 acres at this time last year, said Capt. Chris Bruno of the California Department of Forestry and Fire Protection.
Cal Fire is conducting training in all of its programs, from helicopter rescues to field crews, and is bringing in seasonal employees to support operations with a view to reaching the maximum headcount – which averages 10,000 employees. in June or July, he said.
The presence of La Niña could also cause problems in places other than California.
La Niña influences the climate around the world and is cyclical. It can bring drought to some parts while bringing torrential rains to others.
Both La Niña and El Niño are major disturbances,” said climatologist Bill Patzert. Some weather disasters around the world have been blamed on climate change, but they are actually typical of the La Niña impacts we have seen in the past, although they may be intensified or changed by warming from burning fossil fuels , said.
“La Niña and El Niño have always left large global footprints,” Patzert said.
While California had the driest months of January, February and March on record, Alaska and the Pacific Northwest were wet. Across the Pacific Ocean, Australians were fleeing record flooding. A prolonged drought gripped equatorial East Africa, raising the specter of famine for millions of people in the Horn of Africa. At the same time, parts of South Africa, such as Durban, received record rainfall. Torrential rains caused flooding and landslides in Rio de Janeiro.
There are also other influences. La Niña tends to weaken the wind current in the Caribbean and tropical Atlantic, which contributes to increased hurricane activity in the Atlantic basin. Both 2020 and 2021 were active hurricane seasons, with 2020 entering the record books as the year with the most named storms of any season on record.
This year, Colorado State University forecasts have called for 19 named storms, including nine hurricanes. This would be the seventh consecutive above-average Atlantic hurricane season, according to Patzert.
In the northern United States, La Niña is often associated with cooler and stormier than average conditions and increased precipitation. In the southern United States, they are known for their warmer, drier, and less stormy conditions.
Fortunately, La Niña does not last forever.
Both La Niña and El Niño are part of what is called the El Niño Southern Oscillation, or ENSO. Between the two is a neutral phase, which is what meteorologists thought we were heading towards this spring.
Meanwhile, according to forecasts, the dryness in the western United States has a silver lining, at least for southern and central California. While the National Fire Center predicts most of the northern portion of the state will have significant above-normal fire potential through August, forecasters are forecasting near or below-normal fire activity in the southern portion.
That’s because there hasn’t been enough rain to grow the grasses that often fuel fires in low-lying southern and central California, said US Forest Service meteorologist Matt Shameson. .
“I would say that the vegetation that will become fuel for the fires is ankle-deep or calf-deep,” he said. “Normally, they are knee-high to waist-high.”
The region hasn’t seen any significant grass fires so far this year, which typically start in lower elevations in mid-April, he added.
Northern California has seen more rain, especially between late March and April, so there is a more robust grass presence, which helps spread the fire into the trees, he said. Also, Northern California has more vegetation overall, so fires are not typically limited by the amount of dry vegetation available.
“I think this year is going to be very similar to last year: Very similar conditions are expected,” Shameson said. Southern California saw fewer major fires than average and burned less area, while Northern California broke records with the Dixie Fire, which burned nearly a million acres and tore through the Sierra Nevada for the first time in the history.
“I can tell you: Another great fire season is expected up north,” he said.
The effects of these repeated large and severe fires have the potential to be ecologically devastating and pose a real risk of compromising the state’s climate goals, experts say. The Sierra Nevada and South Cascade mountain ranges, which currently store about half of the carbon captured in California, lost 1.1 million tons of stored carbon due to wildfires, drought and invasive pests between 2018 and 2019 alone , according to recently published research by UC Berkeley scientists.
“That’s a 35% reduction in just one year,” said author Alexis Bernal, a research specialist at UC Berkeley’s Stephens Laboratory. “And we know that these disturbances are only going to increase in frequency and intensity with climate change.”
She and other scientists are calling for land managers to make forests more resilient by removing vegetation and increasing the use of controlled fires to reduce the density of forests so they are affected less easily by flames. intensity.
Without action, the Sierra Nevada and South Cascades region is projected to lose more than 75% of its carbon stocks by 2069, sending some 860 million metric tons of carbon dioxide into the air.
“That means that the Sierra Nevada and South Cascade region will no longer be a carbon ‘eater’, as it is now,” he said. “It will be a source of carbon.”
Large, high-intensity burns can also cause ecosystem collapse by turning forests into grasslands and scrub, he added.
“These landscapes can stop being forests and that would be devastating for all living things, including us, who depend on these forests to survive,” he added.