Typically around this time of the year, just as the peak of hurricane season is approaching, the Mississippi River runs 3 to 5 feet high at New Orleans.
This year, however, the river has flowed past the city at more than 11 feet above sea level for 292 days. It dropped below that level only this week.
If a hurricane does come, it could push enough storm surge up the river to send floodwaters washing over the levees that protect New Orleans, officials say.