What's the worst natural disaster that could hit New York City in our lifetime? [closed]

Question

I'm writing a post-apocalypse story that takes place in New York, mainly the city as the survivors escape the island to the outer boroughs. Anyway, living in New York all of my life, the worse that I've seen is Hurricane Sandy. What I'm aiming for is something natural, but something that could happen at a moment's notice, hence the apocalypse. I've read some theories about global warming and the weather in general, and I've read stories like Stephen King's "The Stand" and the "Maze Runner" series by James Dashner, especially the prologue where they talk about the sun flares.

So, I don't want to go supernatural like "The Stand", and also don't want to go so far into the future that I have to make up tech or language like "Maze Runner". So, what's the worst that can happen to the world, specifically New York, weather wise that would begin this apocalypse?

(PS: I was aiming for New York freezing over and practically becoming the Arctic but it appears that hurricanes are more possible?)

What I've read so far:

http://www.popularmechanics.com/science/environment/natural-disasters/what-happens-when-a-super-storm-strikes-new-york-6323032

http://www.cracked.com/article_20384_the-5-major-cities-most-likely-to-be-spectacularly-destroyed.html

Thanks for all your scientific theories in advance! :-)

*** UPDATE: To answer some of the comments, this story is focused on New York, but it doesn't necessarily mean that the disaster in New York was just a sole event versus being a chain of events caused by something world-wide. As a survivor in NY though, I'd assume that the least of your concerns or even knowledge due to being cut off from society is what's going on with the rest of the state, country, or world itself. And when I say "escape" I guess what I mean is leaving the island in search of other survivors and finding a stable and safe place to be versus the city. Since Manhattan is an island, and if the disaster is related to the ocean (hypothetically), I'd think the inner boroughs would be safer than the island so to me, these were the logical places that survivors would aim for if the city is screwed.

Anyway, looking at the answers now. :-)

Answer 1

For a coastal city like New York the obvious choice is a Tsunami. These can be triggered a number of ways (Earthquake, Volcanic explosion, Landslip, Meteor strike in ocean) and even a high tech first world country would only get a few hours warning depending on where the trigger event happens.

Read up on Krakatoa for the volcano cause, Japan recently had an earthquake-caused one. You can look at La Palma in the Canary Islands for the Landslide trigger although there is some debate as to just how large the Tsunami would be.

Krakatoa:

This would involve a new hot-spot appearing in the crust and a volcano forming off the coast of New York (which would take several years at least). The side of that volcano would then collapse letting sea-water in. The resulting explosion and tsunami could then be devastating and that final act would happen very quickly.

http://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa#Final_explosive_eruption

The pressure wave generated by the colossal fourth and final explosion radiated out from Krakatoa at 1,086 km/h (675 mph).It was so powerful that it ruptured the eardrums of sailors on ships in the Sunda Strait, and caused a spike of more than 2½ inches of mercury (ca 85 hPa) in pressure gauges attached to gasometers in the Batavia gasworks, sending them off the scale. The pressure wave radiated across the globe and was recorded on barographs all over the world, which continued to register it up to 5 days after the explosion. Barographic recordings show that the shock wave from the final explosion reverberated around the globe 7 times in total. Ash was propelled to an estimated height of 80 km.

Earthquake:

Even in non-geologically active areas earthquakes can still occur, although they are rarer. In order to generate a large tsunami a moderately sized earthquake would normally be combined with an underwater landslip as happened in Japan.

http://www.nbcnews.com/science/environment/paris-sized-landslide-may-have-doubled-size-japanese-tsunami-study-n216941

They later found evidence on the seafloor of a landslide with a horizontal footprint about the size of Paris, measuring 40 kilometers by 20 kilometers (25 miles by 12.4 miles), and 2 kilometers (1.2 miles) thick. The landslide created a focused tsunami wave that, when combined with the power of the earthquake, reached epic proportions, he said.

Landslide:

Some islands, particularly volcanic ones, have vast amounts of rock and earth in potentially unstable positions. A collapse in that island that happened fast enough and in the right direction could potentially trigger enormous tsunamis.

http://en.wikipedia.org/wiki/Megatsunami#Canary_Islands

However, the western half of the volcano has an approximate volume of 500 cubic kilometres (120 cu mi) and an estimated mass of 1.5 trillion metric tons (1.7×1012 short tons). If it were to catastrophically slide into the ocean, it could generate a wave with an initial height of about 1,000 metres (3,300 ft) at the island, and a likely height of around 50 metres (164 ft) at the Caribbean and the Eastern North American seaboard when it runs ashore eight or more hours later.

Meteor:

A meteor impact into water would in many ways be more destructive than one into land. Huge waves would radiate out in all directions causing the coast to be battered by at least one and possibly multiple (as the waves bounce around) tsunamis.

http://news.ucsc.edu/2003/05/355.html

A computer simulation of an asteroid impact tsunami developed by scientists at the University of California, Santa Cruz, shows waves as high as 400 feet sweeping onto the Atlantic Coast of the United States.

Man Made: (See Sheraff's answer for more details)

If too much were extracted from the wrong parts of continental shelves then that could in itself trigger the underwater landslide that then triggers the Tsunami. For example Methane Hydrate extraction in the wrong places could cause just this scenario to happen.

http://www.dlr.de/blogs/en/desktopdefault.aspx/tabid-6192/10184_read-189/

If methane hydrates were ever extracted from continental shelves without appropriate precautionary measures being taken, the disaster scenario painted by Schätzing in ‘The Swarm’ could occur: without methane hydrates, the shelves on the coasts could become unstable, gigantic landmasses could start to slip and that in turn could trigger tsunamis. Experts are taking these risks seriously and are only experimenting on the extraction of methane hydrates in flat storage locations far from continental shelves.

Answer 2

Plague

Diseases are adapting to modern day medicines at a frightening rate. New York is a very densely populated area, there is only limited healthcare available. Consider the number of people the average citizen meets in a day, the number of people to use the same taxi, the number of people crammed in a subway car.

If a disease which was immune to a couple of the standard antibiotics mutated inside one of the 8,400,000 people living there it would spread incredibly rapidly. There are only hospital beds for 59,000 of them in the state.

• Healthcare would crumble, not only from primary infections but all of the other diseases which also need treating
• Infrastructure would shut down because there aren't enough people to drive the subway, man the banks/shops/restaurants, work in the hospitals
• People wouldn't be able to work, homes would be repossessed. Bad debt!
• Quarantine zones would need to be established, this will concentrate the disease in the city and limit food, medicine, fuel and other resources required.

Now scale it up

• The USA would lose a massive economical powerhouse (even if the disease is beaten the damage to the economy would be massive)
• I've already mentioned bad debt, suddenly banks have mortgages which aren't being paid. This causes the same sort of problems we saw in 2008 (and are still recovering from 6 years later).
• What impacts the US impacts the word, damage to stock markets, pensions and investment firms across the world

In short, crowded populations help diseases spread and are more dependent on imports from the surrounding area. It would be The Black Death all over again (interestingly the first occourances of multi drug resistant Yersinia pestis have now been seen in Madagascar).

Scared yet?

Answer 3

Methane hydrates destabilization (either from extraction or from a local or global, temporary or long-term warming of the ocean around it) could cause a landslide around the very unstable volcano Cumbre Vieja, Canary Islands, triggering a minor earthquake that would result (through a chain of event detailed below) in a tsunami 50 meter high wiping out New York at a thousand kilometres per hour.

This is in my opinion, the most likely yet worst thing that could happen nowadays, at any time, without any warning, and with absolutely no way of stopping it.

In 1949 the sleepy old dog Cumbre Vieja sprang into action with a bang. The eruption came from one of its craters, at the top of the San Juan volcano. It opened up a fault. It's hard to spot with the naked eye, but it runs for kilometres along the western flank of the island, just below where we're standing. It's possible that the rock at the heart of La Palma has been fissured. At the time, a section of the Cumbre Vieja ridge slipped four metres downwards into the ocean. [We]'ve been monitoring the area for the past few years. It's highly likely that the next eruption will cause the western flank to break off entirely, owing to the unusually large amount of groundwater trapped within the rock. As soon as a new burst of hot magma enters the volcanic vent, the water will expand and evaporate in an instant. The resulting pressure could easily blast the western flank into the water. It's already been destabilised, and the eastern and southern flanks are pushing against it. Five hundred or so cubic kilometres of rock would collapse into the ocean.

The consequences are too dire to imagine. Volcanic islands have a tendency to get steeper with age. Eventually a section breaks off. The authorities on La Palma don't want to face the truth. It's not a question of if it will happen, it's a question of when. In a hundred years? A thousand? The only thing we can't be sure of is the timing. The volcanoes here don't give much warning.

The mass of rock would displace vast quantities of water. A dome would form on the surface of the ocean. According to our estimates, we'd be looking at a speed of impact of three hundred and fifty kilometres per hour. The fallen debris would extend sixty kilometres over the seabed, stopping water flowing back over the landslide, and creating an air cavity that would displace far more water than the volume of the rock. There's some debate about what happens next, but none of the scenarios are especially comforting. The landslide would create a mega-wave off the coast of La Palma, with a probable height of six to nine hundred metres. The wave would set off across the Atlantic at a thousand kilometres per hour. Unlike earthquakes, landslides and slope failures are point events, which means the wave's energy dissipates as it radiates across the ocean. The further it travels from its source, the flatter it becomes.

The Canary Islands would be wiped out in a flash, then an hour later, a hundred-metre-high tsunami would wash over the northwest African coast. Six to eight hours after the eruption, a fifty-metre wave would sweep over the Caribbean, laying waste to the Antilles and flooding the east coast of America from New York to Miami. Soon afterwards the wave would hit Brazil with similar force. Smaller waves would travel as far as Spain, Portugal and the British Isles. The consequences would he devastating, even in central Europe. The European economy would collapse.

[This fifty meter wave] would be enough to flatten New York. The impact of the wave would release more energy than the United States uses in a year. It doesn't matter how tall a building is – it's the base that takes the force of the tsunami. The rest of the building collapses, regardless of how many storeys there are.

There are two ways of destabilising the western flank of the island: either Cumbre Vieja erupts, or there's an underwater avalanche. The rock will sink into the depths, and that in turn will prompt a minor earthquake and destabilise the Cumbre ridge. The earthquake might even trigger an eruption, but in any event the western flank will detach.

from The Swarm by Frank Schatzing

Answer 4

For any particular calamity, there are ways around it (in particular prepared scenarios how to deal with it). In my opinion, when things start looking really ugly, is when multiple things hit at once. For that I recommend for your book besides the main damage-dealer, something else to severely hit morale. In particular, the survival depends very much on spirit, for example in the case of sea-survivors vomiting (from being sea-sick) in rafts has detrimental effects because it very much worsens the mood, and survival rates drop then unexpectedly fast, from weeks to mere days or hours.

Some examples:

• A calamity: Tsunami that floods the whole area but leaves most structures intact, there is not enough potable water, disease start to spread, but things are still manageable. Then, a secondary shock (perhaps which makes the first a foreshock) that crumbles some symbolic building or kills some charismatic leader.
• A nightmare with a Philip K. Dick like twist: A potential terrorist attack that spreads panic, among others causing crime to go rampant, then military steps in with brutal force, however, it is very hard to say who is a bad guy, and who is not. Unexpectedly a nuke goes off, people all around work very hard to get others to safety and treated by medics. Then we learn (e.g. a scene with confused doctors) that the real terrorist attack was a virus, and the nuke was to save the rest of the area/coast/country which is now doomed because of our heroic effort. (Of course it's up to you, whether the virus is natural enough for you).
• We did this to ourselves: you don't need any special technology, to imagine that one could overextend the subway and road network underneath the city (e.g. several levels deep). In case of hurried, underfunded development, a subsidence could easily happen, perhaps related to even some minor earthquake or a groundwater reservoir (e.g. in your story the ground below Manhattan might not be a solid bedrock, the true geological data could have been altered for some greedy people to get lots of money). Pair that up with unusual drought and you have a tragedy ready. Then, as the situation is getting worse (fallen buildings, lots of casualties, crowded hospitals, lack of potable water), people learn that the medical treatment they received force them to rely on costly medication for next few months, which makes the crime rate go up and up at which point the government declares martial law and (by mistake or panic or overzealous officer) Manhattan is sealed from the coast. That generates even more panic, power struggle at the top creates a delay enough that the decision cannot be safely reversed, hell ensues.

I hope this helps ;-)

Answer 5

Climate change is probably the most dangerous threat to coastal cities, not just New York. The problem with New York is that it's close to the sea and many of the infrastructures are close to sea level. As you mentioned, Hurricane Sandy made huge damage, partly because New York is not equipped or built to deal with that kind of problem. The geographic position of the city is really not helping here since Manhattan is surrounded by water and it's pretty flat. Also, an urbanized coast means no natural protection form the winds/waves.

A hotter planet means more energy and that energy is released in different form, including more frequent and more powerful hurricanes. They form closer to the poles. New York is likely to expect more powerful storms in the near future. It will not destroy the city but it will make life more difficult and will cost billions to clean up.

Typhoon Haiyan/Yoland that devastated the Philippines was one the strongest hurricane ever recorded. The most powerful wind at more than 200 km per hour. Buildings in NYC are not built to resist powerful winds. Tall structures must already deal with strong winds high above the ground but if you add an hurricane, it might cause some serious damage.

The rising of the sea is not a very big problem because it's gradual. Even if we expect the worst, (1 meter during the next 100 years) it's manageable. More water mean more damage during the storm but New York can build a dike to lessen the damages. But on the long term, if we don't change our gas emission it is highly probable that cities like New York will be flooded under several meters of water making life very hard for the people there. Eventually, the buildings will collapse because of the non-stop water flow and the corrosion from the sea water.

Answer 6

A solar storm probably isn't the worst thing that could happen, since it most likely wouldn't be powerful enough to destroy individual electronics, but it could wipe out our power/communication grids for a few weeks/months.

Answer 7

The absolute worst disaster that could hit New York City:

Rogue neutron star.

Any "worse" disaster would be easier to see coming (like a rogue black hole or something.) Neutron stars are pretty much non-reactive and don't give out much sign of their presence, and are effectively unstoppable.

Any "lesser" disaster or more localized disaster (Tsunamis, Earthquakes, Supervolcano eruption, etc.) would be much more survivable. Many Skyscrapers are earthquake and Tsunami resistant, a sudden volcano would have an avoidable epicenter, and any disaster that didn't affect the world as a whole would leave many of external response teams to come help out.

Granted, the rest of the world is pretty much toast too. But New York is part of the world. National Geographic did a pretty interesting documentary called 'Evacuate Earth' of what such a disaster would probably shape up like.

Answer 8

I'm not affiliated in any way with the author and it's been a number of years since I read the book but IIRC there's a chapter in this book that lays out exactly what would become of NYC in the absence of humanity.

http://www.worldwithoutus.com/index2.html

From the WP article on the book:

He explains that sewers would clog, underground streams would flood subway corridors, and soils under roads would erode and cave in. From interviews with members of the Wildlife Conservation Society and the New York Botanical Gardens Weisman predicts that native vegetation would return, spreading from parks and out-surviving invasive species. Without humans to provide food and warmth, rats and cockroaches would die off.

(As pointed out by @bowlturner this is is probably a comment, but is too long)

Answer 9

Some sort of extra galactic entity like a comet or asteroid contains a previously undiscovered or theorized type of matter that has a new type of energy signature that disrupts magnetic and electrical functions.

The impact significantly alters the magnetosphere and the energies of earth in such a way that any attempt to generate electricity more than a spark results in effects similar to a localized EMP. No electronics work anymore, and no new electronics can be created because of the EMP effect that results from the magnetic field created by energizing something, and the new energy type that now permeates the Earth, reacting with each other.

Metallic objects all behave strangely from seeming to flow like water, to shattering into dust like a crystal reacting to certain harmonic frequencies. Literally throwing the world back into the stone age. Most of the buildings in Manhattan have been destroyed or rendered effectively unusable by this phenomena.