Hurricane Maria has now caused the longest blackout in US history

Only 30 percent of Puerto Ricans have power, extending the island’s lead in this outage.

It’s been more than 40 days since Hurricane Maria ravaged the electrical grids of two US territories, Puerto Rico and the US Virgin Islands. And yet only about 30 percent of utility customers in Puerto Rico have had their power restored. Across the US Virgin Islands, 84 percent, or more than 40,000 customers, still don’t have electricity either.

Which means that this is now officially the longest blackout in US history, according to an assessment by the Rhodium Group, a policy analysis firm.

Rhodium compared the power outages stemming from Hurricane Maria with those from other events in US history. As you can see, Hurricane Maria has disrupted electricity more than any other event by a long shot:

 Rhodium Group

Peter Marsters, a research analyst at the Rhodium Group, explained that the numbers reflect how many utility customers lost power multiplied by how long they were without power.

And the term “customer” obscures the true impact of these outages. A household of two and a household of 10 both count as one customer each, since there’s usually only one electricity bill per home.

It’s worth noting that of the top 10 outages, nine were due to hurricanes, and eight occurred after 2000. This is in part due the fact that populations are growing and more are living in harm’s way, increasing the impact of extreme weather.

Though power grids across the United States do try to anticipate blackouts, they only prepare for disruptions measured in minutes, not days, weeks, or months.

“These mostly weather-driven events are magnitudes above [outages in] day-to-day grid operation,” Marsters said.

In Puerto Rico and the USVI, the outages have lead to ongoing health and environmental crises as idled sanitation systems have forced some to drink from contaminated wells and other water sources. The power losses are making it more difficult to contain hazardous waste.

The outages have proved deadly, with people unable to use lifesaving medical equipment like dialysis machines, and they’ve contributed to Puerto Rico’s official death toll of 51.

As we’ve reported here at Vox, the actual number of fatalities is likely much higher, a development that has prompted lawmakers to ask for an audit. BuzzFeed also reported that there have been more than 900 cremations across the island since the hurricane without medical examination.

Such outages also carry a massive price tag for the economy.

The financial services firm Allianz estimated that a 30-minute power loss costs an average of $15,709 per customer for medium and large industrial facilities, while an eight-hour outage costs an average of $94,000.

“Even short blackouts — which occur several times a year in the US — add up to an annual estimated economic loss of between US$104 and US$164 billion,” the firm found.

The power losses will also have huge financial consequences for Puerto Rico, which was already in dire economic straits before the storm.

Outages from Hurricane Maria are also having knock-on effects. As Vox’s Yochi Dreazen reported from Puerto Rico, the power losses are “significantly slowing the entire US relief effort, and preventing other vital parts of the island’s battered infrastructure from coming back online.”

Power restoration work in these hurricane-hit territories is proving slow, sporadic, and expensive. Much of the infrastructure has been physically knocked down, and hardware has to come in through ports that are already clogged with relief supplies.

While there has been some progress in getting the lights back on and entrepreneurs are using the region to enact their vision for a cleaner, more resilient power grid, most in Puerto Rico and the US Virgin Islands are relying on stopgap measures like gasoline-powered generators.

“These numbers are going to rise,” Marsters said. “Every customer-hour loss adds to the cumulative total.”