The late-June derecho storm that swept across the region was serious. But a new Pepco report published yesterday on the utility’s response to mass power outages given a hint as just how serious a storm it was.

According to the report, 483,639 Pepco customers were without power in the region during the outage’s peak period. No storm in the last two years has come close to that number—the closest competitor was a July 2010 storm that left 323,662 without electricity. During the worst of it, some 75,896 Pepco customers in D.C. were without power, representing 29 percent of all customers in the city. In 2010, that number was 14 percent. That many people without power means plenty of unbilled hours for Pepco. But just how many? Just over 24 million hours across the region, with 3.6 million of those being in D.C.

And you’d expect plenty of phone calls to Pepco, right? Indeed—596,113 of them from June 29 to July 7. As for Pepco’s website, well, storms are good for traffic. In the first three days after the storm, Pepco reported 108 million hits—more than the first five months of 2012 combined. Pepco’s mobile application also saw impressive growth, with downloads having increased from 19,400 before the storm to 54,530 after it—a 280 percent increase. Mobile devices accounted for 83,000 customer outage reports, 14 percent of all reports.

And yes, as expected, the majority of the power outages were caused by trees or limbs coming down on overhead wires. According to the report, 60,305 D.C. customers lost power because of fallen trees or limbs; 391,619 region-wide suffered that fate. During its recovery effort—which involved 2,613 external personnel and 783 external vehicles—Pepco replaced 17,747 feet of wires in D.C. and 373,101 feet region-wide.