PHOENIX (AP) — Much of the American West has been blasted with sweltering heat this week as a high pressure dome combines with the worst drought in modern history to launch temperatures into the triple digits, toppling records even before the official start of summer.
Record daily highs were seen this week in parts of Arizona, California, New Mexico, Montana, Wyoming and Utah. Phoenix, which is baking in some of the U.S. West’s hottest weather, was forecast to hit 117 degrees (47 Celsius) Thursday and 116 degrees Friday and Saturday.
“Very dangerous record breaking heat should continue today across the deserts with well above normal highs,” the National Weather Service’s Phoenix staff wrote on Facebook. “A very good day to stay indoors.”
WHY IS THE AMERICAN WEST SO HOT THIS WEEK?
The heat comes from a high pressure system over the West, a buckle in the jet stream winds that move across the U.S. and vast swaths of soil sucked dry by a historic drought, said Marvin Percha, a senior meteorologist for the agency in Phoenix.
He and other scientists say the heat wave is unusual because it arrived earlier and is staying longer than in most years.
“June last year, things seemed pretty normal,” noted Park Williams, a University of California, Los Angeles, climate and fire scientist. “The record-breaking heat waves came in August and September.”
But with such an early heat wave this year, “this could be the tip of the iceberg,” Williams said.
WHAT ROLES DO DROUGHT AND CLIMATE CHANGE PLAY?
A two-decade-long dry spell that some scientists refer to as a “megadrought” has sucked the moisture out of the soil through much of the Western United States. Researchers said in a study published last year in the journal Science that man-made climate change tied to the emission of greenhouse gases can be blamed for about half of the historic drought.
Scientists studying the dry period that began in 2000 looked at a nine-state area from Oregon and Wyoming down through California and New Mexico and found only one other that was slightly larger. That drought started in 1575, a decade after St. Augustine, Florida, was founded and before the Pilgrims landed on Plymouth Rock in 1620.
The hot weather can be tied to the drought drying out the landscape. Normally, some of the sun’s heat evaporates moisture in the soil, but scientists say the Western soil is so dry that instead that energy makes the air even warmer.
“When the soil is wet, heat waves aren’t so bad,” said Williams, who has calculated that soil in the western half of the nation is the driest it has been since 1895. “But if it’s dry, we are under extreme risk.”
HOW DO RECENT WILDFIRES FIGURE INTO THIS?
Scientists say the wildfires that have erupted in recent days have been fed by the excessive heat across the region. Climate change contributes to the drought conditions and makes trees and shrubs more likely to catch fire.
At least 14 new wildfires broke out this week in Montana and Wyoming as the record heat sparked an early start to the fire season. Firefighters also battled blazes in Arizona and New Mexico.
“From a fire potential standpoint, what is capable this year, it is certainly much more severe than we’ve seen in the past,” U.S. Department of Agriculture fire meteorologist Gina Palma said in a climate briefing Thursday.
Palma said the drought-related fire risks were especially pronounced in higher elevations across much of the U.S. West, from the Rocky Mountains down into the Southwest and parts of California.
“You will be seeing very extreme fire behavior, certainly conditions that we would not normally see in June,” she said.
IS THIS THE NEW NORMAL?
A growing number of scientific studies are concluding that heat waves in some cases can be directly attributed to climate change, said Kristie L. Ebi, a professor at the Center for Health and the Global Environment at the University of Washington.
That means the U.S. West and the rest of the world can expect more extreme heat waves in the future unless officials move to cut down on greenhouse gas emissions, Ebi and other scientists say.
A study last month estimated the percent and number of heat deaths each year that can be attributed to human-caused climate change. It included about 200 U.S. cities and found more than 1,100 deaths a year from climate change-caused heat, representing about 35% of all heat deaths in the country.
On average each year, Phoenix has 23 climate-triggered heat deaths, Los Angeles has 21 and Tucson has 13, the study said.
“Climate change is harming us now,” Ebi said. “It’s a future problem, but it’s also a current problem.”
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Associated Press Science Writer Seth Borenstein contributed from Washington. Follow Snow on Twitter at https://twitter.com/asnowreports and Borenstein at https://twitter.com/borenbears.
Drought saps California reservoirs as hot, dry summer looms
OROVILLE, Calif. (AP) — Each year Lake Oroville helps water a quarter of the nation’s crops, sustain endangered salmon beneath its massive earthen dam and anchor the tourism economy of a Northern California county that must rebuild seemingly every year after unrelenting wildfires.
But the mighty lake — a linchpin in a system of aqueducts and reservoirs in the arid U.S. West that makes California possible — is shrinking with surprising speed amid a severe drought, with state officials predicting it will reach a record low later this summer.
While droughts are common in California, this year’s is much hotter and drier than others, evaporating water more quickly from the reservoirs and the sparse Sierra Nevada snowpack that feeds them. The state’s more than 1,500 reservoirs are 50% lower than they should be this time of year, according to Jay Lund, co-director of the Center for Watershed Sciences at the University of California-Davis.
Over Memorial Day weekend, dozens of houseboats sat on cinderblocks at Lake Oroville because there wasn’t enough water to hold them. Blackened trees lined the reservoir’s steep, parched banks.
At nearby Folsom Lake, normally bustling boat docks rested on dry land, their buoys warning phantom boats to slow down. Campers occupied dusty riverbanks farther north at Shasta Lake.
But the impacts of dwindling reservoirs go beyond luxury yachts and weekend anglers. Salmon need cold water from the bottom of the reservoirs to spawn. The San Francisco Bay needs fresh water from the reservoirs to keep out the salt water that harms freshwater fish. Farmers need the water to irrigate their crops. Businesses need reservoirs full so people will come play in them and spend money.
And everyone needs the water to run hydroelectric power plants that supply much of the state’s energy.
If Lake Oroville falls below 640 feet (195 meters) — which it could do by late August — state officials would shut down a major power plant for just the first time ever because of low water levels, straining the electrical grid during the hottest part of the summer.
In Northern California’s Butte County, low water prompts another emotion: fear. The county suffered the deadliest U.S. wildfire in a century in 2018 when 85 people died. Last year, another 16 people died in a wildfire.
Walking along the Bidwell Canyon trail last week, 63-year-old Lisa Larson was supposed to have a good view of the lake. Instead, she saw withered grass and trees.
“It makes me feel like our planet is literally drying up,” she said. “It makes me feel a little unsettled because the drier it gets, the more fires we are going to have.”
Droughts are a part of life in California, where a Mediterranean-style climate means the summers are always dry and the winters are not always wet. The state’s reservoirs act as a savings account, storing water in the wet years to help the state survive during the dry ones.
Last year was the third driest on record in terms of precipitation. Temperatures hit triple digits in much of California over the Memorial Day weekend, earlier than expected. State officials were surprised earlier this year when about 500,000 acre feet (61,674 hectare meters) of water they were expecting to flow into reservoirs never showed up. One acre-foot is enough water to supply up to two households for one year.
“In the previous drought, it took (the reservoirs) three years to get this low as they are in the second year of this drought,” Lund said.
The lake’s record low is 646 feet (197 meters), but the Department of Water Resources projects it will dip below that sometime in August or September. If that happens, the state will have to close the boat ramps for the first time ever because of low water levels, according to Aaron Wright, public safety chief for the Northern Buttes District of California State Parks. The only boat access to the lake would be an old dirt road that was built during the dam’s construction in the late 1960s.
“We have a reservoir up there that’s going to be not usable. And so now what?” said Eric Smith, an Oroville City Council member and president of its chamber of commerce.
The water level is so low at Lake Mendocino, along the Russian River in Northern California, that state officials last week reduced the amount of water heading to 930 farmers, businesses and other junior water-rights holders.
“Unless we immediately reduce diversions, there is a real risk of Lake Mendocino emptying by the end of this year,” said Erik Ekdahl, deputy director for the State Water Board’s Division of Water Rights.
Low water levels across California will severely limit how much power the state can generate from hydroelectric power plants. When Lake Oroville is full, the Edward Hyatt Power Plant and others nearby can generate up to 900 megawatts of power, according to Behzad Soltanzadeh, chief of utility operations for the Department of Water Resources. One megawatt is enough to power between 800 and 1,000 homes.
That has some local officials worrying about power outages, especially after the state ran out of energy last summer during an extreme heat wave that prompted California’s first rotating blackouts in 20 years. But energy officials say they are better prepared this summer, having obtained an additional 3,500 megawatts of capacity ahead of the scorching summer months.
The low levels are challenging for tourism officials. Bruce Spangler, president of the board of directors for Explore Butte County, grew up in Oroville and has fond memories of fishing with his grandfather and learning to launch and drive a boat before he could drive a car. But this summer, his organization has to be careful about how it markets the lake while managing visitors’ expectations, he said.
“We have to be sure we don’t promise something that can’t be,” he said.
Low lake levels haven’t stopped tourists from coming yet. With coronavirus restrictions lifting across the state, Wright — the state parks official for Northern California — said attendance at most parks in his area is double what it normally is this time of year.
“People are trying to recreate and use facilities even more so (because) they know they are going to lose them here in a few months,” he said.
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Associated Press writer Brian Melley in Los Angeles contributed to this report.