It was literally an event felt around the world.

The Hunga Tonga volcano erupted Friday morning, sending clouds of ash into the atmosphere, and causing tsunami warnings to be issued all around the Pacific Ocean, including along the B.C. coast here in Canada. The sounds from the volcano were heard as far away as Alaska, and even Yukon Territory and Northern Alberta. Shockwaves rippled around the globe, with instrumentation in Switzerland, nearly on the other side of the world from Tonga, detecting an increase in atmospheric pressure as a result of the volcano.

The volcano is suspected to be responsible for one death in Tonga, as well as two people in Peru as a result of the tsunami recorded there. Others are reported missing in other areas, including Tonga and Fiji. Surveillance flights from New Zealand and Australia are surveying the damage now that the ash cloud has dissipated. Those nations are also coordinating assistance for the island nation.

When a large volcanic eruption occurs like this one, there is the possibility that its effects can be felt worldwide. The last eruption of this scale was in 1991 when Mt. Pinatubo erupted in The Philippines, and there were impacts even here in Saskatchewan.

An aerial view of the volcanic activity

We reached out to Dr. James Lee, a Professor of Geology in the Department of Geological Sciences at the University of Saskatchewan. One of the first questions asked was whether this eruption would have similar global impacts.

“I think globally, this particular eruption probably has really only two relatively minor effects,” Lee explained. “The first one is there will be some disruption to air traffic. The ash plume from this volcano is estimated to be at least 20 kilometres high and obviously there’s potential damage to aircraft engines as we saw back in 2010 with the Icelandic volcano.”

The other impact is one that could be appreciated here in Saskatchewan. Lee pointed out that the very tiny particulates ejected into the atmosphere will circulate throughout the globe, and we can expect to see very colourful sunsets over the next few months.

Two other impacts gave a cause for concern for those who study volcanoes, but those appear to have abated. The first was tsunamis, with warnings issued around the Pacific. The tsunami waves reached over a metre in Tonga, but by the time the wave made its way over to Canada, it was between 10 and 26 centimetres along Vancouver Island.

The other potential impact is something that was seen in 1991 with the Pinatubo eruption – a cooling of the climate. This cooling can be caused by two different aspects of an eruption, Lee said.

“The first, of course, is the ash particles themselves,” he explained. “If there’s a lot of ash being ejected into the atmosphere, they can reflect sunlight, and of course, that could cause global cooling.”

The other way a volcano can cause global cooling is the release of sulphur dioxide into the atmosphere, and this combines with water vapour and reflects sunlight.

“From what we’ve measured so far, it seems like the concentrations of sulphur dioxide are very, very low and so this won’t have much of an effect either,” Lee went on to explain.

Other volcanic eruptions have had the potential to distribute the ash across wide swaths. There were reports of ash from the Mt. St. Helen’s eruption of 1980 settling here in Saskatchewan. However, even if the ash manages to travel the 10,000+ kilometres east to west on the globe to make it this far, the chances of any of the ash from this eruption making it to the Land of Living Skies is very, very slim.

“Because of our atmospheric circulation path, volcanic eruptions at sort of mid to high latitudes well away from the equator tend to mostly affect only that hemisphere where they occur,” Lee pointed out. “So, for instance, northern hemisphere volcanoes would tend to affect the northern hemisphere more and vice versa, so this one being in the southern atmosphere means that most of the effects will happen in that hemisphere.”

As so often happens when a geological event like a volcanic eruption, or even an earthquake, happens anywhere in the world, many people wonder what the chances are of something like this having an impact locally. Lee explained that here in Saskatchewan, we are in probably one of the safest places, geologically speaking, in Canada. However, it doesn’t mean there would be no impacts from something like a volcano erupting close by.

Some of the closest volcanoes in Canada are located in British Columbia and the Yukon. Lee noted some examples are Mt. Garibaldi and Mt. Meager. The latter was responsible for the largest eruption that geologists are aware of in Canada, happening roughly 2,300 years ago. This eruption deposited ash as far away as Alberta.

The greatest volcanic hazard for Canada, though, may actually be south of the border.

“There are many active volcanoes in the Cascade Mountain ranges just to the south of British Columbia, in Washington State, and of course, Mt. St. Helen’s is probably the most famous of those,” Lee explained. “The volcano closest to the Canadian border, which you can see if you’re ever flying into Vancouver Airport, you can actually see, it is called Mt. Baker. That’s only 23 kilometres from the border and it last erupted in 1943.”

The circumstances of the eruption could also have some benefits for science, particularly for NASA. Lee elaborated on the situation by pointing out how it is currently believed the volcanoes on the red planet were formed underwater.

“Of course, we have no model to study these things, and so this volcano in Tonga can potentially serve as a model for how underwater volcanoes form, which would then give us an idea for instance how deep the water might be, or how long the water lasted on the surface of Mars,” Lee explained. “So, it could have some very, very interesting scientific implications.”

images courtesy NOAA/GOES-West