The phrase "a string of crises" is correct and usable in written English.
It can be used to describe a series of difficult or challenging situations that occur in succession.
Example: "The country has faced a string of crises over the past few years, including economic downturns and natural disasters."
Alternatives: "a series of crises" or "a chain of crises".
The country has had a string of crises and coups since independence in 1966.
That precipitated a string of crises which resulted in it losing its national portfolio status.
For the European Union, struggling with a string of crises, the accord is also an important victory.
He harshly condemned state interference in civil society, calling for reforms that seemed to have been deferred by a string of crises this fall.
As a string of crises and Mr. Yeltsin's desultory rule drained Moscow of money and influence, the far-flung provinces have increasingly made their own way, and some leaders have become corrupt, autocratic or both.
Another focus of the meetings in Dublin was the bundle of initiatives known under the umbrella name banking union — intended to break the vicious circle involving indebted sovereign governments and shaky banks that helped unleash a string of crises repeatedly threatening to sink the euro over the last three years.
A string of manufactured crises followed.
But after a string of financial crises, it became a big net lender.
However, from the late 1990s onwards he was beset by a string of personal crises and clashes with the law caused by drug use.
In May 1931 payment difficulties at the Creditanstalt, Austria's largest bank, set off a string of financial crises that enveloped much of Europe and were a key factor forcing Britain to abandon the gold standard.
In the past year, the North has prompted a string of diplomatic crises by enriching uranium, expelling inspectors from the International Atomic Energy Agency IAEAA), extricating itself from the Nuclear Non-Proliferation Treaty and extracting plutonium (despite a 1994 agreement to freeze plutonium production).
