The amazing story of Lake Toba – Sumatra’s great natural wonder

As you descend through calm beauty and spellbinding views into the small township of Parapat, it’s hard to imagine this was the epicentre of a violent upheaval that literally rocked the world around  74,000 years ago. Some scientists believe it even threatened the beginnings of humanity. 

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THIS VAST AND BEAUTIFUL lake is the result of Mt Toba blowing its top. Scientists rank it as the world’s most explosive known super volcano eruption.

Richard Roberts, Professorial Fellow at the University of Wollongong, writes that the volcano ejected more than seven trillion tonnes of material, with at least 800 cubic km spewed as ash across the Indian Ocean and the lands of South and Southeast Asia. (1)

Residue fragments as far away as Africa

A plume of ash, tephra and pumice covered millions of square kilometres of the planet’s surface in a blanket of debris 1 to 5m deep (3–15 ft).

Tephra residue (rock fragments) from the blast has been identified in locations more than 9,000 km away in southern Africa.

The blast also pumped staggering quantities of sulphurous gases into the atmosphere to be transported around the globe by weather systems.

Sulphate spikes and ash from the explosion have been identified in drill cores from as far as Greenland and 

fiery volcanic eruption

These short videos briefly explain what happened when Mt Toba blew up and how it led to the creation of Lake Toba and Samosir Island. 

World-wide cooling impact for up to 1,000 years

Though there are conflicting opinions and on-going debate, many scientists believe the stratospheric dust and ash clouds from the eruption would have reduced world temperatures by at as much as 10 degrees centigrade, creating a dark and chilling winter for around 10 years.

Some argue it had a cooling impact on world climate for as long as 1,000 years.

Professor Stephen Oppenheimer, an expert in prehistory and human migrations, sees the Toba ‘mega-bang’ as one of the most significant events shaping the history of early mankind.

Early humanoids illustration

Illustration –  Charles R Knit – Wiki Commons

The eruption happened as early humans were beginning to move out of Africa and the Middle East into the rest of the world.

The sudden dark and cold of the volcanic winter is thought to have killed vegetation and animals and disrupted human food supplies.

Genetic evidence suggests the number of surviving homo sapiens (our ancestors) fell to no more than a few thousand!

Eight times more powerful than greatest Yellowstone event

The eruption is estimated to have been eight times as powerful as the biggest known Yellowstone super volcano blast in North America around two million years ago.

The quantity of rock, dust, and ash it blasted into the air is estimated to be almost three times as great as that from the third major Yellowstone eruption in Wyoming 640,000 years ago. It was 2,800 times greater than that of the Mt St Helens explosion in Washington State in 1980.

Scientists say Mt Toba is at least 1.3 million years old and has produced at least six definitive eruptions since its super blast — and maybe more.

The most recent is believed to have occurred about 56,000 years ago. And yes, Toba is still LIVE – there is magma churning around deep beneath the lake.

But the scientists also do not see any likelihood of a new eruption any time soon.

Indeed, they suggest eruptions at nearby Mt Sinabung from the same magma reservoir are probably relieving Toba pressures.  

Why Lake Toba ranks as one of the world’s natural wonders

The magnificent and beautiful Lake Toba of today is the legacy of that dramatic and significant moment so long ago in the history of our world and our species. 

Panoramic View of Lake Toba

A stunning panorama (TOP) and Parapat – a popular destination on the shore of Lake Toba and a main departure point for Samosir Island.

Lake Toba is the caldera of the ancient volcano and is one of the world’s largest volcano craters. It is 100 km long, 30 km wide and located 905m (2,970ft) above sea level. It’s up to 505m (that’s 1,657ft) deep.

The township of Parapat on the eastern shore of the lake is one of the main centres where passenger and vehicular ferries embark for Samosir Island in the middle of the magnificent lake. 

Vehicular ferry Lake Toba

Vehiculara nd passenger ferries provide access to Lake Toba’s Samosir Island. 

But there is much more to Toba than the fascinating saga of its origins. It offers spectacular panoramas over the waters to the steeply rising rim of the caldera, with its waterfalls and lush vegetation, and to the mountains beyond.

The lake, the island and the surrounding region is unquestionably a Sumatran and national treasure.

It should rank up there among the world’s great natural attractions like the Grand Canyon, Australia’s Uluru, the Great Barrier Reef, Vietnam’s Ha Long Bay and the Niagara, Victoria, and Iguazu falls (Brazil and Argentina).

But strangely, outside the realms of academic scientists and more adventurous travelers, in much of the world it is not widely known. 

Toba and Samosir Island are of great significance to the Batak people

Samosir Island and Lake Toba are the beating heart of the cultural traditions of the Batak clans of North Sumatra. They believe that this is where they had their beginnings.

At about 650sq km the area of Samosir, is almost as big as Singapore.

You will have time to ponder those remarkable events of so long ago as you take the 45-minute ferry voyage from Parapat to the island 

With a population of around 140,000, Samosir is home for several Toba Batak communities, most maintaining cultural traditions. It is also a place of relics from bygone eras.

Drone view Samosir Island Lake Toba

The popular Tut Tut Peninsular area of Samosir Island, Lake Toba

Through the 1980s and into the 1990s Lake Toba attracted steady waves of overseas visitors, especially backpackers for many of whom it became almost a rite of passage. But this faded after the Asian financial crises of 1997-98.

A destination waiting to be truly discovered

Toba remains a destination still waiting to be truly ‘discovered.’ Over recent years it has attracted only a trickle of international visitors, many from nearby countries like Malaysia and Singapore.

Tourist numbers in 2019 totalled only around 260,000

The Government is actively promoting greater tourism for Indonesia and Lake Toba has been given a high priority.

Upgraded silangit airport - access to Lake Toba

International travellers can fly direct to te upgraded Silangit Airport for easier access to Lake Toba. 

Until recently visiting Lake Toba usually requiring a two-way road trip from Medan. However, since 2017 Silangit Airport south of the lake has been progressively upgraded to cater for more than half a million passengers a year.

Pre-pandemic it was attracting direct international flights from Malaysia and Singapore, as well as direct domestic services from major Indonesian cities.

Hopefully these links will be restored as the COVID Pandemic is brought under control.


Lake Toba is one of those places we will much better appreciate if we know its mind-boggling back story.

We can immediately enjoy its scale, its stunning beauty, its people, and the many things to see and do on Samosir Island, and around the lake. But it all takes on much more significance when we know the history.

Toba has good accommodation and plenty of cafes and restaurants offering quality local, Western, and fusion foods, especially in the Tut Tut Peninsular area of Samosir.

You also will have an opportunity to meet and learn about the culture and history of the gracious and interesting Toba Batak people, who still maintain proud clan traditions.

Lake Toba ought to be a major international tourist destination, and no doubt it will become one in the years ahead. But right now, outside holiday peaks you can usually spend time there without competing with tourist hordes.

You can read more about what to expect in my related article Special places and experiences at magnificent Lake Toba

References –

  1. Armageddon and its aftermath: dating the Toba super-eruption –
  2. Science Daily –

FOOTNOTE: If you are interested in  learning more about the Toba explosion, its ramifications, and the scientific debate about its impacts, you can view more videos via the links below. One paints a scary picture of the consequences if the blast happened in the modern day – just take another sip of your coffee and remind yourself that the super explosion happened around 75,000 years ago and there have been suggestions that the next one, if any, could be another 25,000 years into the future … on second thoughts, could that mean you should be visiting Lake Toba soon, so you don’t miss out?