The Federal Reserve Bank of Philadelphia’s index of economic activity just fell off a cliff:

Optimists on the U.S. economy have conceded that things are weak, but they’ve argued we’re not falling off a cliff.

But on Thursday, Wall Street got a hint that a cliff dive could be imminent.

Philly The Philadelphia Federal Reserve Bank’s index of economic activity in the mid-Atlantic region plummeted to a negative 30.7 this month, down from a positive 3.2 in July and the lowest since a negative 30.8 reading in March 2009 — in the depths of the last recession.

Get ready for President Bachmann and similar disasters.