It has been conjectured that the changes were due to ashes or dust thrown into the air after the eruption of a volcano ( a phenomenon known as " volcanic winter " ) , or after the impact of a comet or meteorite . The evidence of sulfate deposits in ice cores strongly supports the volcano hypothesis ; the sulfate spike is even more intense than that which accompanied the lesser episode of climatic aberration in 1816 , popularly known as the " Year Without a Summer " , which has been connected to the explosion of the volcano Mount Tambora in Sumbawa
Year Without a Summer
Year Without a Summer
Extreme weather events of 535–536