Skip to main content

What Time of Year Do Volcanoes Mostly Erupt?

During the winter months, the summit of the Hawaiian volcano, Mauna Loa  (elev. 13,679'), often receives a blanket of snow

During the winter months, the summit of the Hawaiian volcano, Mauna Loa (elev. 13,679'), often receives a blanket of snow

An Educated Guess Turns Out to Be Correct

Two years ago, the new year ushered in a number of active volcanoes, some of which were old stand-byes to the world of vulcanologists, while others appeared to have just awakened from a deep slumber. Pictured below is the Fagradalsfjall volcano, which captured the world's attention when it came to life and sent long flows of red-hot lava streaming across the Icelandic countryside.

Other places around the globe that saw rise to sudden and unexpected volcanic activity included Italy (Mt. Etna), Soufriere Hills on Montserrat Island in the Caribbean (April 2021), the Nyiragongo volcano in the Congo (May 2021), Cumbre Vieja volcano in the Canary Islands (September 2021) and then finally Kilauea in Hawaii, which began its colorful display in September 2021. This shield volcano sent glowing lava flows across the Hawaiian landscape before ceasing its activity in December of that same year.

The above information comes from memory and, as a result, bears no statistical significance. To conclude that volcanoes have a time of year when they display an increased frequency of eruption, extensive data research is needed.

In March 2021 the Fagradalsfjall volcano erupted and continued spouting lava for six months

In March 2021 the Fagradalsfjall volcano erupted and continued spouting lava for six months

The Statistical Research

A few years back (2004), researchers at the University of Cambridge (UK) did a statistical analysis of how often volcanoes erupt, and in the process, they came up with a surprising find. The frequency of these natural wonders varies throughout the year, with the winter months of November, December, January, February and March being the time with the highest number of active volcanoes.

Their statistical analysis showed that the increase was most noticeable in regions with numerous active volcanoes. These places include the Andes, Central America, the Kamchatka Peninsula and Japan. All total, volcanoes around the planet showed an 18% higher chance of activity during these months.

The human view from space cannot detect small changes in the shape of our planet.

The human view from space cannot detect small changes in the shape of our planet.

The Scientific Reasoning

The geological explanation for this recently-discovered phenomenon is complex and perhaps even a bit bizarre. The increased frequency during the winter months is partially caused by ice build-up in the Northern Hemisphere, brought on by less daylight, colder temperatures and widespread snowfall.

While the northern half of the planet is experiencing winter, the Southern Hemisphere is in summer. Since most of this part of the globe is ocean, there is an increase in water evaporation brought on by longer days and higher temperatures.

From this point, it is believed that the loss of water in the South makes the southern half of our planet lighter, thus aiding in the overall global distortion.

In essence, both environmental changes act together to actually change the shape of our planet. These changes put additional stress on Earth's crust, so we have more active volcanoes.

Volcanic activity also occurs in Antarctica, despite the severe cold.

Volcanic activity also occurs in Antarctica, despite the severe cold.

The Effects Are Universal

One interesting side note is that the winter increase in volcanic activity was not limited to the Northern Hemisphere but actually occurred all across the planet. The Andes of South America is one place the Cambridge researchers noted as having an increase in volcanic activity from November to March. Though not all of this massive mountain chain lies south of the Equator, the portion from Peru to Chile definitely does, and as a result, many of these places were included in the survey, as were sites from New Zealand.

The underwater Tonga volcano, locally known as Hunga Ha'apai by island Natives, the volcano erupted in January 2022, sending huge ash clouds high into the atmosphere.

The underwater Tonga volcano, locally known as Hunga Ha'apai by island Natives, the volcano erupted in January 2022, sending huge ash clouds high into the atmosphere.

A Warning From the University of Cambridge

Not long ago, July 2022 to be exact, some researchers from the University of Cambridge published an article in the journal Nature, exploring the idea that the overall worldwide population is ill-prepared for a major eruption. They say the Tonga underwater eruption in the South Pacific was a warning.

Had this violent geological event been a tad larger or persisted for a longer time, we might have seen changes in global weather patterns similar to when Tambora blew its top way back in 1815. For everybody's enlightenment, the April eruption created a huge ash cloud, resulting in the "Year Without a Summer," which happened in 1816, some 16 months after the volcano exploded.

The British researchers also note that if this undersea blast had occurred in a more populated place, like the Mediterranean Sea, damage to our modern way of life and highly mechanized food production system could have been quite severe.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2023 Harry Nielsen