Last time, it threw smoke 12.4 miles high and led to the cancellation of passenger flights.
Icelandic volcano Grimsvotn may erupt in the near future, researchers say.
This is evidenced by a number of signs, such as the frequency of small earthquakes and swelling on the surface of the volcano, caused by the approaching lava, writes The Conversation.
Grimsvotn is Iceland's most frequently erupting volcano. It has erupted at least 65 times over the past 800 years. During a major eruption in 2011, it threw smoke and ash 12.4 miles high. About 900 passenger flights in northern Europe were canceled.
Volcanologists reassure: usually large eruptions of Grimsvotn alternate with small ones. Most likely, the new eruption will not be as large as in 2011. But volcanoes are very unpredictable systems, so you can't be one hundred percent sure of this forecast, scientists say.