"A high payout in the European telecom sector is nowadays more a danger signal that the dividend yield is not sustainable, " he adds.

WSJ: Investors Hang Up on Europe's Telecom Stocks

There are currently no severe flood warnings, which signal a danger to life.

BBC: Wet weather affects Britain's rail and roads

"Well intentioned efforts to reduce exposure to nuts actually fans the flames, since they signal to parents that nuts are a clear and present danger, " said Professor Christakis.

BBC: peanuts

One danger signal will be if the Chinese banks start using their idle domestic deposits to fund a lending bender abroad.

ECONOMIST: Japanese banks

With my indicators on a sell signal for bonds since August 16, I have been warning about bonds being overbought and in danger of rolling over into a serious correction for several months.

FORBES: Who Will Buy All Those Treasury Bonds When The Fed Stops?