SAN FRANCISCO — Pacific Gas and Electric’s unprecedented outages are affecting hundreds of thousands of Northern California customers — and its own website.

PG&E’s website was down, slow or inaccessible for the past two days as the utility began warning people of outages and then proceeded to cut power. In public communications from PG&E on its social media accounts, website and text messages directly to consumers, the company directed people to its website for information about the potential outages. Instead, many users received error messages.

This is the first time PG&E has instituted widespread outages during weather that could be conducive to wildfires. The announcement caught many by surprise. People began flooding PG&E’s website Tuesday to learn more about what they could expect in terms of the scale and length of the event.

PG&E says the site was never completely inaccessible, but that it was slow to load amid heavy traffic.

PG&E spokesman Paul Doherty said the utility doubled its server capacity in advance of the outages but that the traffic levels were eight times what PG&E expected and slowed the site significantly. He said he did not know exactly how many people had tried to visit the site.

Doherty said the utility made efforts to inform affected customers over email, text and phone calls so they would know whether they were likely to be in the outage zone. The company says it has since addressed the issues with its website.

“If someone’s power was being shut off, they would have been notified by PG&E directly, with a first and second message,” Doherty said. “But there was still lots of confusion if folks were being impacted or not.”

Starting on Oct. 9, hundreds of thousands of California homes and businesses lost power in an unprecedented outage by Pacific Gas & Electric. (Jonathan Baran, James Pace-Cornsilk, Drea Cornejo, Adriana Usero/The Washington Post)

Some Californians took to social media to express their outrage at PG&E for not anticipating the volume of traffic the website would receive or finding alternative ways to communicate with customers quickly enough — particularly considering the company is headquartered in tech-centric San Francisco.

“PG&E could have worked with Silicon Valley tech & social networks … to ensure valid information is distributed across all platforms,” tweeted Matthew Keys, a Solano County-based digital editor. “But they relied on their own unreliable website.”

The power outages are the largest in California’s history, with some 800,000 customers affected. On Tuesday afternoon, as word spread of the imminent outages, people began visiting the PG&E website and reporting on social media that the site wouldn’t load or that they received error messages. Some said they couldn’t access any part of the site; others said they could access the main site but not the maps associated with the shut-off.

Paul Wilson, a San Francisco-based brand consultant, said it was a “nightmare” trying to get information from the website in the hours before the outage. When he was finally able to access the PG&E site, the text on the page directed him to another site, which was inaccessible. He said he finally gave up and found a map and additional information from the San Francisco Chronicle. San Francisco was not affected by the outages.

Others lambasted PG&E for not informing people sooner about the outages, and for initially not using social media to publish detailed maps of the affected areas, updating them as conditions changed. The Pleasanton Police Department made light of the situation by creating an exaggerated and incomprehensible map of the outage zones that went viral on social media.

PG&E began the blackouts early Wednesday in advance of dry, windy weather that increases the risk of dangerous wildfires. As the outages were instituted, PG&E posted messages on its website and social media feeds stating that it was experiencing a high volume of traffic to its website and was “working as quickly as possible to restore access.” Later that day, the utility directed consumers to a website set up through geographic information platform ArcGIS.

That, too, was inaccessible to many customers.

On Thursday, Google’s autofill suggestions for users who typed “pge website” included “pge website down” and “pge website not working.”

Californians have expressed fear that the blackouts will harm the sick and elderly, lead to mobile outages and result in millions of dollars in lost business income.

Doherty said late Thursday morning that PG&E had further increased its server capacity — beyond the doubling it did before the shut-offs — to accommodate the increased traffic.

The utility said about 600,000 customers were without power midday Thursday. While the utility told people their power could be out for as long as five days, Doherty said PG&E has restored power to 127,000 customers.