FAA declares rare nationwide ground stop on flights, with more than 10,000 delayed so far

JUST IN: More than 10,000 US flights delayed with no timeline to resolve the nationwide FAA ground stop, officials say, citing 'extraordinary circumstances' while Homeland Security reports no indication of an attack.

More than ten thousand flights are now delayed, and the FAA still has no timeline to lift its nationwide ground stop.

The agency is calling these extraordinary circumstances, and that word choice matters. The FAA does not ground the entire country lightly. The last time Americans saw anything on this scale was September 11, 2001.

Homeland Security says there is no indication of an attack. That rules out the worst explanation, but it leaves the question of what exactly has failed open. Aircraft are sitting at gates across the country right now, and you can see the scene here, terminals full of planes going nowhere.

Every hour this continues, the backlog compounds. Crews time out, connections collapse, and even after the stop lifts, it will take days for the system to recover. Ten thousand delays is the number as of tonight. By morning it will be worse.

This is Sara White, reporting for HIT.