Summer officially begins next week — and in California, it may be a cruel one.

Even with the upheaval of the pandemic mostly behind us, the menace of drought and rising temperatures is threatening to derail the return to normal.

This year’s extraordinarily dry, warm weather, which is expected to continue in the coming months, is stoking fears of a multitude of problems: increasing water restrictions, extreme heat, blackouts, wildfire and smoke — potentially all of the above in one vicious swoop.

“There are just all these things when it comes to climate and weather that Californians are having to think more about,” Mark Ghilarducci, director of the Governor’s Office of Emergency Services, recently told The Chronicle. “We know scientifically that the climate is changing. It’s the cascading impact of that change that is hitting all of us.”

The Union of Concerned Scientists, a nationwide advocacy group led by scientists and policy experts, went as far as using the term “danger season” this month to characterize the summer that may lie ahead for parts of the United States.

Already in California, climate volatility, as palpable as it’s been, has joined the list of reasons people cite for wanting to move away, after soaring home prices, high taxes and traffic. The state’s population, which had grown for decades, dropped in each of the past two years.

“We have people say they’re concerned about drought, they’re concerned about wildfire,” said Scott Fuller, founder of LeavingTheBayArea.com, a 7-year-old real estate company that helps people relocate. “We’ve had clients say this is literally the final straw.”

Historic drought: Recent climate twists have helped propel California into a third straight year of drought. Seven of the past 10 years have been dry. Some scientists say the state is in a mega-drought not seen in 1,200 years.

With reservoirs approaching historic lows, exposing telltale bathtub rings and cracked earth, and with aquifers emptying amid heavy pumping, several water agencies have begun restricting water use by customers. These include some of the state’s biggest municipal suppliers.

A workman moves irrigation pipes to water crops covered by plastic to reduce water evaporation on a farm outside Santa Rosa.

The East Bay Municipal Utility District, which serves Oakland and Berkeley, passed an “excessive use” ordinance this spring, establishing fines for customers whose water consumption exceeds a certain threshold, which is generous to begin with but could tighten.

Water agencies in the South Bay this month began enforcing a twice-a-week outdoor watering policy, with penalties of $500 and possibly more, and the giant Metropolitan Water District in Southern California started limiting watering to just one day a week in certain spots.

While bright green lawns will be the next sacrifice made by millions of Californians, Gov. Gavin Newsom is also already asking residents to limit showers to five minutes as well as swap out baths for these shorter showers. Earlier this year, state regulators also banned many outdoor watering activities, such as hosing down driveways and filling up ornamental fountains.

“We’re going to have to change our lifestyles,” said Richard Frank, professor of environmental practice at the UC Davis School of Law and director of the school’s California Environmental Law & Policy Center. “We’re seeing some of that (change) already, but more is needed. I don’t think abandoning thirsty lawns and swimming pools in the backyards of middle- and upper-class neighborhoods is too much to ask.”

The public’s tepid response to calls for voluntary conservation over the past year, Frank said, means future water restrictions will have to be that much more stringent to protect supplies.

Wildfire danger: The drought also leaves California’s hills and valleys primed for burning, yet again.

While recent rains may help take the edge off the fire season initially, the benefit won’t last. The first three months of the year, when California typically gets a good portion of its rain, marked the driest start to a calendar year on record for most of the state. And that’s after two dry years that also sapped forests, grasslands and chaparral of moisture and fire resiliency.

The National Interagency Fire Center has pegged Northern California, including the Bay Area, for above-average fire potential in July and August, with the exception of some coastal spots. By September, all of the north state is projected to be at high risk.

“It’s impossible to predict numbers, but I can tell you with the drought conditions that persist, we expect to see fire behavior similar to what we’ve seen the past few years,” said Chris Amestoy, a staff chief for the state’s Cal Fire agency.

The 2020 and 2021 fire seasons were the biggest in modern California history. Last year, more than 2.5 million acres burned, an extraordinary run of flames that included destruction of the Gold Rush-era town of Greenville in the northern Sierra and the gutting of the community of Grizzly Flats west of Lake Tahoe.

Smoke and flames from the LNU Lightning Complex fires rise near the Paradise Valley Estates in Fairfield in 2020.

In 2020, more than 4 million acres were charred. That fire season yielded such giants as the SCU and LNU lightning complexes in and around the Bay Area as well as the unprecedented 1 million-acre-plus August Complex in the coastal mountains to the north. At times, fire, and smoke, seemed to be everywhere in 2020.

The recent surge in wildfire is caused not only by the changing climate, fire experts say, but to the buildup of vegetation that’s resulted from decades of misguided fire suppression.

Amestoy said Californians shouldn’t necessarily panic about what might come this year but simply recognize the dangerous conditions that exist and be prepared.

“It’s just a change in mind-set,” he said. “We have to have a realization of the environment we’re in now.”

Lethal heat: Part of this new reality is extreme heat.

The National Oceanic and Atmospheric Administration is projecting a summer of higher-than-average temperatures for California and most of the West while the warming climate leaves the region more susceptible to longer, more brutal heat waves.

Last July, the Pacific Northwest, including California’s far north, was baked by an unparalleled bout of heat that shattered temperature records, pushing Portland to an astonishing high of 116 degrees and resulting in hundreds of deaths along the West Coast. A year earlier, Southern California saw a similar period of lethal temperatures in August, with Death Valley reaching 130 degrees, probably the highest temperature ever recorded on Earth.

“The climate is capable of generating heat waves that are really much stronger than people can imagine,” said Park Williams, a climate scientist at UCLA. “There’s really no reason a heat wave like (what we’ve seen the past few summers) couldn’t occur in the Bay Area.”

Acknowledging limited awareness about the dangers of heat, Newsom this spring began an “extreme heat action plan” that lays out a strategy of educating people about the risks, planning cooling centers and readying emergency assistance.

Extreme heat, according to the Environmental Protection Agency, has been the leading cause of weather-related deaths in the United States over the past 30 years.

“The human body is only so good at cooling itself off,” Williams said. “If a record-shattering heat wave were to occur in the Bay Area, you would find a lot of people in trouble quickly.”

The drought, Williams added, makes life-threatening scorchers even more likely because there’s less water evaporating into the atmosphere to keep things cool.

Large areas of the bed of Lake Tahoe are exposed because of drought conditions in October.

Energy supply: The combination of heat and drought is also a problem for the power grid, potentially leaving California’s energy production short of what’s needed to keep the lights on.

With less water in reservoirs, less hydropower can be expected this year. Last year, Lake Oroville, the largest state-managed reservoir, for the first time stopped producing power entirely because there wasn’t enough water to spin the electrical turbines.

A recent report published by the U.S. Energy Information Administration estimates that California’s hydroelectricity supply could fall by nearly half during the depths of the current drought, from 15% of the state’s total generation to 8%.

California energy officials are already bracing for a possible shortage. The electric grid, they say, could see a time when supply lags demand by 1,700 megawatts in coming months, about the amount needed for up to 1.7 million homes.

Such a lag would probably come during hot weather, when demand for power tends to be higher as people ratchet up their air conditioners, and during early-evening hours, when solar electricity is also in short supply. If it’s really hot, state officials project the power deficit could be as great as 5,000 megawatts.

While California would ask people to conserve and try to buy power from out of state if supplies here drop, the fear is that a large heat wave could affect much of the West and hamper sources of electricity elsewhere, too. That could leave no choice but for some Californians to go without.

Amid the August scorcher two years ago, which caused the grid to run low, state energy regulators ordered utilities to halt power to hundreds of thousands of people over the course of two days.

“Climate change continues to cause unprecedented stress on California’s energy system,” wrote officials from the California Energy Commission, Public Utilities Commission and California Independent System Operator in a joint media report last month. “It continues to threaten reliability and put Californians at risk of additional outages.”

Utilities, including PG&E, have also been increasingly proactive about cutting power to individual communities when there are high winds, to prevent live wires from sparking a wildfire.

Ghilarducci, the head of the Governor’s Office of Emergency Services, said blackouts are one of many problems his agency is trained to respond to and help communities contend with — on top of the other climate-related perils of heat, wildfire and water shortages.

Needless to say, there are other problems, including earthquakes, that could arise.

Customers shop in the dark at La Tapatia Market in Napa during one of PG&E’s public safety power shut-offs in 2019.

“Last year, we had something like 18 or 19 major wildfires, statewide civil unrest and the pandemic,” he said. “We always have to be thinking about the worst-case scenario.”

Ghilarducci’s advice for residents: be familiar with the hazards in your area and have an emergency plan that includes knowing who to call and where to get help.

“There’s just so much bad stuff,” he said. “We don’t want you all to have to think about it to the degree that we do.”

Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com Twitter: @kurtisalexander

Kurtis Alexander is an enterprise reporter for The San Francisco Chronicle, with a focus on natural resources and the environment. He frequently writes about water, wildfire, climate and the American West. His recent work has examined the impacts of drought, threats to public lands and wildlife, and the nation's widening rural-urban divide.

Before joining the Chronicle, Alexander worked as a freelance writer and as a staff reporter for several media organizations, including The Fresno Bee and Bay Area News Group, writing about government, politics and the environment.