10 years after blackout, US grid faces new threats

The U.S. electrical grid is better managed and more flexible a decade after its largest blackout but remains vulnerable to increasingly extreme weather, cybersecurity threats, and stress caused by shifts in where and how power is produced. The following is a slide presentation for the 10-year anniversary of a massive power failure caused the largest power outage in the nation's history, affecting 50 million people in parts of seven states and Canada. (AP)