Worst Natural Disasters by Type

Whilst man has proved very effective at killing himself there is still some healthy competition from Mother Nature. The natural world contain any number of potentially deadly animals but the effects of all these put together are almost insignificant when planet Earth itself turns against us.

With the exception of war and epidemics nothing kills in numbers like a natural disaster. And with the exception of an all out nuclear war nothing has the ability to kill so indiscriminately and quickly as natural disaster. In the blink of an eye hundreds of thousands can be left dead and sometimes the aftermath can be just as deadly.

One of the truly terrifying things about natural disasters is they can transcend all of our technology and we are virtually powerless to stop their destruction. Perhaps the only comfort is that we have become a lot better at predicting these catastrophes and as a result millions of lives have been saved. Unfortunately this is not always the case and even in the most developed nations we can be caught off guard with devastating consequences such as the 2011 Japanese earthquake and tsunami.

For the purpose of this article we shall look at the different kinds of natural disaster and the worst examples of these. I have also focused on those that have occurred in relatively modern times.

10. Wildfires

Wildfire / bushfire

Wildfires can occur anywhere there is sufficient combustible vegetation – all it takes is for it to be sufficiently dry and a source of ignition. This can come from lightning, volcanic eruption or even sparks from falling rocks. However, more commonly it is some form of human intervention that causes these fires, whether it be accidental or arson.

Once established wildfires can turn a peaceful woodland into hell on earth and can become virtually unstoppable. Burning at temperatures of over 800 °C (1,470 °F) wildfires also travel at great speed. Whilst in heavily forested areas they move at jogging pace this accelerates to running pace in open grasslands and can be even faster with a strong tailwind. What makes the fires particularly dangerous is their unpredictability; the fire-front can move forward, as expected, or completely change direction. Flying embers can even start further fires as far away as 20km (12 miles).

One of the truly awesome aspects of these forest fires is they are capable of influencing the local weather. They can form pyrocumulus clouds, which may create lightning, and strong winds which swirl at speeds equivalent of a tornado.

1871 Peshtigo Fire, Wisconsin

The deadliest wildfire ever recorded took place in Peshtigo, Wisonsin in 1871. The estimates on how many people were killed vary between 1,500 and 2,500.

Over a million acres of forest were burned during the fire but it was when it reached the small town of Peshtigo that most of the casualties happened. Fanned by strong winds the fire had become a superheated firestorm with tornado-like fire whirls. Some survivors reported seeing rail cars and houses tossed into the air by these winds.

It is believed the cause of the inferno was small fires set to clear farm land which were whipped up by strong winds, soon escalating out of control.

9. Blizzards


Photo: ©Steve Webster (adapted from) | License

By definition a blizzard is a severe snowstorm with high winds which last several hours, if not days. The dangers of blizzards are the reduction in visibility caused by the snow being blown around, extremely low temperatures and the fact that when the snow does settle it forms deep drifts.

Just being caught momentarily in a blizzard can be dangerous enough as the extreme wind chill is enough to cause frostbite. Further exposure will result in hypothermia pretty much regardless of how much clothing you have. The obvious solution is not to stay outdoors, but this is easier said than done when gale force winds make it almost impossible to see beyond the end of your nose.

Many blizzard related deaths are those who are caught out while driving. With snow drifts often reaching several metres in depth cars can become buried with no way of getting out. Although this is definitely a better place to be than outside the temperature will soon begin to drop well below freezing.

1972 Iran blizzard

The deadliest blizzard in history occurred in February of 1972 in Iran. A week of extremely low temperatures and strong winds affected much of the country, but it was the south that was worst hit.

With reports of as much as 8 metres (26ft) of snow falling whole villages were buried. The city of Ardakan bore the worst of the snows and in outlying villages such as Kumar and Kakkan entire populations perished.

It is estimated that by the end of the week more than 4,000 people had died, mostly from being buried in the snow.

8. Avalanches


Avalanches occur when unstable snow and ice on a mountainside breaks away and hurtles down the slope carrying rocks and other debris with it. There are several factors required to create the right conditions for an avalanche, for example the slope must be the right steepness; too flat and there is not sufficient gravity, too steep and the snow never builds up. Once the potential is there for an avalanche all that is required is a trigger.

Now I’m going to disappoint a lot of people by telling you that loud noises starting avalanches is a bit of an urban myth. On the other hand it is a fact that over 90% of avalanche victims actually start the avalanche themselves.

Once triggered avalanches pick up speed alarmingly quickly. Within 5 seconds thousands of tons of ice and snow can be travelling at 80 mph (130 km/h). Some avalanches have been recorded at speeds of over 225 mph (350km/h).

Victims of avalanches fall into three camps. Around three-quarters are killed by asphyxiation. Therefore it is essential to try and get to people as quickly as possible. Survival rates plummet after 20 minutes. Most of the remaining fatalities are caused by trauma; either from being hit by a freight train sized lump of ice or the various other debris carried along with the slide.
Less than one percent die from hypothermia.

Each year 150 people are killed on average by avalanches, but some years are much worse.  During World War I avalanches in the Italian Alps killed an estimated 10,000 Austrian and Italian soldiers within a matter of days. The worst single event though happened in Peru in 1970.

1970 Huascarán avalanche

Triggered by a huge undersea earthquake off the coast of Peru, this was the deadliest avalanche ever recorded. Although the quake caused major devastation over a large area of the country it was the highland town of Yungay that suffered the worst fate.

Without warning the magnitude 8 earthquake caused the glacier on the north face of Mount Huascarán to break up sending an estimated 10 million cubic metres of snow, ice and rocks hurtling down the mountainside at speeds of 120 mph (190km/h). It took only three minutes for the wall of debris to reach the valley below by which time it had picked up thousands more tons of rocks and mud.

Lying in the path of this unstoppable wall of mud, ice and rock was the town of Yungay and its 25,000 inhabitants. With no time to evacuate the town was flattened and buried within seconds killing virtually the entire population.

7. Heatwaves

Heat wave

It may seem a little surprising but periods of hot weather kill more people than periods of extremely cold weather. The exact definition of a heat wave is quite elusive and varies from region to region. For example a heatwave in South Australia may require a temperature of more than  40 °C (104 °F) for three days. However, a heatwave in much of Northern Europe is 10°C (18°F) cooler. This reflects the relative nature of heat waves and how the local infrastructure is set up to deal with heat.

Another factor to be taken into account is humidity; higher humidity can have the same adverse health effects as higher temperature.

Heat becomes dangerous when the body is unable to effectively cool itself, which leads to heat stroke (hyperthermia). This particularly affects the young, old and infirm as cooling requires significant cardiovascular effort. When the body stops regulating its temperature its biochemical reactions are affected and essential metabolic pathways controlling vital cellular operations breakdown.

2003 European heat wave

The summer of 2003 was the hottest since records began in Europe. During July and August southerly airstreams brought hot air up from Africa causing temperatures to rise around 6°C (11°F) higher than seasonal averages. Although this might not sound like a large rise it was sufficient to cause an estimated 70,000 heat-related deaths across Europe.

France was worst hit with nearly 15,000 deaths, virtually all elderly. It was seen as a sad indictment of French society as many of those old people who died lived alone and were unable to cope. It is said many of the bodies were not discovered for weeks with undertakers filled to capacity waiting for relatives, who were unaware, to come and identify bodies.

6. Volcanoes

Sakurajima volcano, Japan

Sakurajima volcano / Photo: Kimon Berlin / License

Volcanoes are named after Vulcan, the Roman god of fire. It isn’t hard to imagine why as they form a direct portal into the fiery mantle that exists just below the Earth’s crust. You could think of volcanoes as a kind of safety valve letting out the gases and molten rock that come under massive pressure from the movement of tectonic plates.

Some volcanoes will contentedly spew out lava and noxious gases indefinitely while others bottle it all up. When this pressure builds up over hundreds, or even thousands of years something has to give, and when it does…

Probably the best known and most dramatic eruption of a volcano in modern history was that of Krakatoa in Indonesia. When Krakatoa erupted in 1883 it was the loudest noise ever recorded; heard over 3,000 miles (4,830 km) the boom ruptured sailors eardrums  40 miles (64 km) away. The power of the explosion was immense, releasing 4 times more energy than the most powerful nuclear weapon ever created.

The first to dies were those on nearby islands who were blasted clouds of debris laden burning ash. However, it was not the explosion itself but the ensuing tsunami that wrought the real carnage. Together the eruption and tsunami left anywhere between 35,000 and upwards of 100,000 dead.

Krakatoa measured 6 on the Volcanic explosivity index (VEI), ranking it as “colossal”. A score of 8 is considered “apocalyptic”. Although Krakatoa is the most famous volcano of modern times,  another in Indonesia scored a 7 on the VEI and, in the long run, caused more deaths.

1815 eruption of Mount Tambora

The eruption of Mount Tambora, on the island of Sumbawa in 1815 was the most powerful volcanic eruption in nearly 2,000 years. The explosion reduced one of Indonesia’s tallest mountains to half its height ejecting 10 billion tonnes of rock in the process. This left a crater 4 miles (7 km) across and 2,000ft (700m) deep.

Along with the explosion a tsunami was triggered, but not on the same scale as that caused by Krakatoa. There are no truly reliable figures on how many people were killed by the eruption itself but estimates put the figure at around 10,000. The tsunami killed many more but it was the after effects of the eruption that claimed the most lives.

The ash that rained down on Sumbawa and the neighbouring islands was over 3ft (1m) deep effectively killing off all crops. Even within 300 miles (500 km) a considerable amount of ash fell. The ensuing shortages of food caused perhaps 100,000 further deaths over the next year. But it didn’t stop here.

Much of the massive amount of ash and noxious gases belched out of the volcano was sent straight into the upper atmosphere where it spread around the world. This caused a significant drop in global temperatures leading 1816 to be labelled the “Year without Summer”. Crops failed around the world for two years as a result of the colder weather and the acidic rain. Whilst it is hard to put a number on the resulting deaths from famine and disease it is likely to have been in the millions.