In the San Francisco Bay Area, one of the largest concentrations of wealth and cutting-edge technology in the world, the shut-off felt like an anachronism, something that might happen in a less-developed country. Long lines formed at gas stations a dozen or so miles from the headquarters of Apple and Google.

“What’s next?” said Robert Cruz Jr., an electrical foreman whose crews have installed fiber-optic cables at Facebook. He was at a gas station in San Jose, the country’s 10th-largest city, filling up a five-gallon container with gasoline for a generator he was on his way to buy from a friend. He and his wife, an executive assistant at Intel, spent Tuesday calling nearby stores for new generators but the closest store that had one was an hour and a half away in California’s Central Valley.

“We’re doing what we can to keep our refrigerator and our freezer going,” he said.

For many, the power shutdown was a reminder of how helpless they were without electricity. While wealthier residents were able to fall back on solar panels and battery systems for electricity, living off the grid was not an option for Sharmaine Lindahl.

The power outage had cascading consequences for Ms. Lindahl and her husband, who live in Arcata, nearly 300 miles north of San Francisco. On Tuesday night, she received a text message from PG&E warning her of the impending power shut-off. Five hours later the lights went out and all of the electrical appliances in her kitchen, the only way she can cook, were useless.

Most businesses were closed in Arcata on Wednesday, she said, and gasoline was scarce.

Wednesday was also her husband’s payday, but the bank was closed and his company paid him in cash because it could not print out checks.

“Our bank account is going to be overdrawn,” Ms. Lindahl said. “We live paycheck to paycheck. So this is going to hit us very hard.”