1The appearance of the comet was seen as a harbinger of doom by the ancient civilization.
2Is the recent increase in extreme weather events a harbinger of the devastating consequences of climate change?
3The company's financial struggles were a harbinger of the industry-wide crisis that followed.
4The discovery of the new species was a harbinger of a major shift in our understanding of the natural world.
5There is a long tradition in literature of using natural phenomena as harbingers of human fate, from Shakespeare's storms to the ominous birds of Edgar Allan Poe.