Heat wave marks end of Sacramento’s second-hottest summer on record

With temperatures expected to top out at 107 degrees on Friday, the heat wave that began baking the Sacramento region Monday may feel like an intense exclamation point to a relatively mild summer.

After all, downtown Sacramento never recorded more than three consecutive days in which temperatures topped 100 degrees.

In reality, though, this Sacramento summer was the second hottest on record, thanks to consistently warm day and nighttime temperatures.

“It was more of a slow burner,” said National Weather Service meteorologist Eric Kurth.

That slow burn is flaring up in earnest at the tail end of the fourth summer of California’s historic drought.

The unseasonably high temperatures have sweeping, statewide repercussions well beyond adding a few extra dollars to a homeowner’s September electricity bill.

Almond farmers across the state face an unexpectedly urgent need to keep their lucrative trees’ roots soaked in the middle of the harvest, when the trees are at their most vulnerable. Fire crews are on high alert in case a spark or discarded cigarette butt ignites grass and brush that have become brittle after four consecutive drought years. Power-grid regulators hope that such a spark doesn’t catch under transmission lines, which will surely strain under a week of ramped up air-conditioning units.

Yet it’s several species of cold-water native fish, already teetering on extinction, that could suffer the most under the unrelenting sun and baking temperatures. One species, in particular, faces an immediate threat.

In a 5-mile stretch of the Sacramento River below Shasta Dam, thousands of baby winter-run Chinook salmon are at a critical stage of their life cycle, when water temperatures above 56 degrees can trigger a die-off.

Last year, dam managers didn’t release enough cold water into the river, and just 5 percent made the transition from eggs to fry and began the journey to the Pacific Ocean in tough, warm conditions. Biologists suspect most of those fish didn’t survive the long journey.

The species has a three-year spawning cycle, meaning that three consecutive fish kills could lead to the end of the winter run as a wild species.

While federal dam managers say they expect to have better success this year, biologists and fish advocates say they’ve been troubled by average daily temperatures at a key point in the Sacramento River repeatedly rising above 58 degrees this summer.

Bill Jennings, executive director of the California Sportfishing Protection Alliance, said the problem won’t get any easier to manage in this week’s heat. He said the high temperatures are sure to cause water temperatures to rise and kill some fish. The question is how many?

“We can hammer the winter run,” he said. “Or we can skate by with the skin of our teeth.”

Shane Hunt, a spokesman for the U.S. Bureau of Reclamation, which manages Shasta and Folsom dams, said water managers are adjusting their cold-water releases accordingly to make up for the sudden spike in temperatures.

“We’re making real-time adjustments,” Hunt said, “and looking ahead a couple of days to make sure we’re staying on track.”

Beyond that, local officials said they hoped Sacramentans don’t start pouring extra water on their lawns, possibly jeopardizing the region’s stellar conservation record in recent months, including a regional average of 38 percent in July. Gov. Jerry Brown has ordered urban water agencies to cut water use by an average of 25 percent, compared with 2013.

“We’re very hopeful that people recognize that this is another symptom of the drought ... and people have to be very careful with their water consumption,” said Rob Roscoe, general manager of Sacramento Suburban Water District. The district has cut its water use 37 percent the past two months.

Human health is becoming an issue, too. Roscoe said the district is reminding its outdoor crews to “stay hydrated.”

Water managers aren’t the only ones adjusting. Almond farmers also are having a stressful week in the sweltering heat, said David Goldhamer, a water management specialist at the Division of Agriculture and Natural Resources at UC Davis.

“This time of the year is actually the most critical time in terms of stress sensitivity of the almond tree,” he said.

In much of California, almond farmers have already broken out the massive machines that shake the nuts from the trees. Goldhamer said the farmers typically leave the nuts to dry on the ground below the trees before they’re scooped up and shipped to processing centers.

Goldhamer said moisture from irrigation and nut drying don’t mix, but if farmers don’t water the trees in this unexpected heat wave, they will have smaller yields in next year’s harvest.

Goldhamer said many growers use blowers to push the nuts out of the way of their water lines and sprinklers.

“But it’s a delicate process. They’ve got to hustle,” Goldhamer said. “This is the time of the year the things going on in the orchard are at the absolute peak because you’ve got harvest, which is a multi-step deal. And you’ve got (almond) prices that are pushing $5 a pound, which is by far the highest it’s ever been. They want to maximize every nut and get every nut possible for their profit, but they still want to take into account the impacts of water management for next year.”

Should the heat wave affect next year’s crop, it could have implications on the state’s agricultural sector. Already, farmers are projected to see their yields decline by 7 percent this year.

After the dairy industry, almonds were the state’s second-largest crop in 2013, the last year for which statistics are available, according to the U.S. Department of Agriculture. The crop was valued at $5.8 billion that year, up from $4.8 billion the year before.

As the almond harvest winds down, fire season remains in full effect. Crews across the state remain on high alert.

“It’s September and October here in California that we experience our largest and most damaging wildfires,” said Daniel Berlant, a spokesman for Cal Fire, the California Department of Forestry and Fire Protection.

Case in point: It was on Sept. 15 last year that the wind-fanned Boles fire in the town of Weed in Siskiyou County burned more than 150 homes – a third of the town’s residences.

Already this year, Berlant says, Cal Fire has responded to more than 5,000 wildfires – 1,500 more than fire crews would fight in an average year.

Kurth, the National Weather Service meteorologist, said the good news is the winds that make late summer and early fall fires especially dangerous aren’t expected this week.

Even so, Friday in Sacramento is likely to break the all-time temperature record for that day of 106 degrees set in 1888.

The all-time high temperature for September is 109 degrees.

“We could be flirting with that record,” Kurth said.

Ryan Sabalow: 916-321-1264, @ryansabalow.