On the island of Krakatau (Krakatoa) in the Sundra Strait, of Indonesia, Sunday, August 26, 1883, was like most days. The island’s residents went about their daily business in routine fashion. There was smoke emanating from three volcanic cones on the island, but that wasn’t unusual. Over the next 48 hours, one of the most notable geological catastrophes on record would erase over 70 percent of the island and thousands of people would be dead following the eruption of the Krakatoa Volcano. Deadly tsunamis would travel for thousands of miles. Weather patterns across the world would be altered for years.
A map showing the location of Krakatau Island in the Sunda Strait. Map Credit- Wikipedia-Public Domain.
A Catastrophe In The Making
Although not technically a meteorological event, the colossal eruption of the Krakatoa Volcano triggered extreme changes in the atmosphere which we will discuss later. I would bet that every meteorologist has heard of and has read about this event.
There were a few telltale signs that the eruption would occur well ahead of time. Seismic activity around the volcano was persistent and earthquakes were felt in Australia.
In May of 1883, steam began to vent from Peroewatan, one of the three cones on the island. Ash was spewed into the atmosphere up to 20,000 feet and explosions could be heard around 100 miles away in what is now Jakarta, Indonesia.
This activity went on a hiatus but it resumed again later in June. Tides were several feet above normal and ships had to be secured in port by chains. More earthquakes were triggered.
Captain H. J. G. Ferzenaar, who was a topographical engineer investigated the Krakatoa islands in early August. He described three major ash columns which obscured the western part of the islands and steam spewed from other vents. He also saw a layer of ash, and a foot and a half thick. He feared a major eruption was immenent and warned against future landings on the island.
Activity continued through the following week and thundering noises were heard across neighboring islands. Residents of these islands held festivals celebrating the natural “light show” in the night skies. Unfortunately, the celebrations would come to an abrupt and tragic end.
An Overwhelming Event
Just before 1 p.m. on Sunday, August 25th, the first blast of the eruption sent gas and debris up to 15 miles high. The worst of it would occur the next morning, however. Four colossal explosions would follow by August 27th.
The sound was deafening. It was estimated that anyone within ten miles of the explosions would become deaf immediately. Eardrums of sailors forty miles away were broken. It’s impossible to imagine the sound. It was estimated to be around 180 decibels. The explosions were heard in Perth, Australia which was 2,800 miles away from Krakatau Island!
Here is one account of the event which appeared in the Atlantic Magazine
“High waves first retreated and then rolled up on both sides of the strait. During a night of pitchy darkness, these horrors continued with increasing violence, augmented at midnight by electrical phenomena on a terrifying scale, which not only enveloped the ships in the vicinity but embraced those at a distance of ten to twelve miles. The lurid gleam that played on the gigantic column of smoke and ashes was seen in Batavia, eighty miles away. Some of the debris fell as fine ashes in Cheribon, five hundred miles to the eastward.”
Two of the cones were submerged in the ocean. Mounds of coral were propelled from the sea to some islands. The explosions ruptured the magma chamber that allowed seawater to contact the hot lava.
In geology, this is called a phreatomagmatic event. The water ash-boiled, creating superheated steam that carried the pyroclastic flows up to 25 miles at speeds exceeding 60 mph.
The eruption is estimated to have had the explosive force of 200 megatons of TNT. The atomic bomb at Hiroshima had a force of 20 kilotons, nearly ten thousand times less explosive than the Krakatoa eruption. The Krakatoa eruption was about ten times more explosive than the Mt. St. Helen’s eruption in 1980.
Immediate Impacts
The explosions sent about eleven cubic miles of debris into the atmosphere which turned the skies dark up to 275 miles away, and they remained that way for three days. Volcanic ash descended on ships nearly 4,000 miles away. Barographs all over the world recorded shock waves.
Each eruption triggered massive tsunamis When the volcano collapsed into the ocean, it generated a tsunami at least 120 feet tall, which was so powerful it tossed blocks of coral onshore. A steamship was thrown one mile inland, killing all 28 crewmen and it destroyed the Islands of Java and Sumatra.
A huge block of coal was thrown onshore at Java Island following the eruption of the Krakatoa Volcano in August of 1883. Photo Credit-Wikimedia Commons- Public Domain.
One tsunami traveled all the way to Aden on the Arabian Peninsula in only 12 hours. All told, over 36,000 people died in this event and 90 percent were victims of tsunamis. The other 10 percent were killed by fast-moving volcanic gases and ash. The official records of the Dutch East Indies Company colony indicate that 165 villages and towns were destroyed near Krakatoa, and 132 were seriously damaged.
Because of the invention and use of the telegraph, this event was the first of its kind to receive worldwide news coverage.
Long Term Impacts
The Krakatoa eruption also produced other impacts. some of which lasted years into the future.
People across the globe could see colorful sunsets and moonlight (from blue to orange and red) for up to two years. In Central America on the other side of the Pacific, the sun looked blue, and floating fields of pumice up to ten feet deep interrupted shipping and trade. Red sunrises and sunsets were often seen along the Eastern Seaboard of the U.S.
Amazingly, fire departments in New York City, Poughkeepsie, and New Haven were called because some residents mistook the vivid sky colors for actual fires.
A series of paintings from 1888 depicting the colorful sky on the East Coast of the U.S. following the Krakatoa Volcano eruption in 1883. Image Credit – Wikimedia Commons- Public Domain.
The volcanic debris in the atmosphere was so great that it filtered the amount of sunlight reaching Earth’s surface, causing global temperatures to drop 1,2 degrees Celcius the next year.
Temperatures didn’t rebound back to average for five years.
A study by Nathalie Schaller, Thomas Griesser, Andreas Marc Fischer, Alexander Stickler, and Stefan Brönnimann, using reconstructed upper-level circulation elds, found that the Krakatoa effects in the first winter after the eruption suggested a strengthened polar vortex in the Arctic stratosphere.
Much of Europe experienced a mild winter at the Earth’s surface, but North and South America experienced a cold winter and those conditions continued into the following winter. The (temperature anomaly) map below is from that study.
The winter of 1884 in the U.S. featured long cold spells, several major blizzards and extremely heavy rainfall across parts of California (in a non-El Niño environment).
Odds And Ends
The massive Krakatau eruption in 1883 wasn’t the first one on the island and it won’t be the last. In 550 AD, a massive eruption at Krakatau tuned the skies dark over Europe which lead to crop failures and famine.
Another eruption occurred in May of 1680. Following the 1883 event a fourth Island, Anka Krakatau or “Child of Krakatoa”, emerged. Occasional eruptions have continued more recently in 2009, 2010, 2011, and 2012, and a major collapse in 2018. The December 2018 event triggered a tsunami resulting in over 425 deaths and over 14,000 injuries.
No volcanic eruption in human history has darkened the entire world. But about 535 AD a volcano at Krakatoa erupted so violently it may have darkened the sky around the world to an extent that it caused famines and threw Europe into the Dark Ages (they are not called the Dark Ages because the sky was dark, rather it was considered to be a period of intellectual darkness).
