Due to the varying size of nuclear bombs, the amount it would take to wipe out New Zealand is hard to calculate. It would take over 7,000 United States W-78 missiles at a 335-kiloton yield, or just less than 100 Tsar Bombas at 100 megatons.

New Zealand is a small-ass country, and nuclear weapons create a big-ass explosion – so it would seem logical to evacuate one’s bowels at the thought of one of those terrifying missiles hitting 100% Pure NZ.

But however small Aotearoa may be, it would still take more than one bomb to wipe us out (should us naughty little kiwis get a bit too big for our boots). So then, how many will it take?

Details about missile size

To start, the answer is actually a question: How big is your bomb?

Not all nuclear weapons are made equal, and to blanket suggest that X amount of kilometres squared would be eviscerated by a nuke in one blast would be a disservice. Indeed, throughout the 1900s, scientists around the world (but particularly the US and Russia) created frightening bombs, capable of wiping out vastly different-sized areas.

Should a nuclear weapon detonate in the air (air burst), both of the weapons described below would have a larger radius.

Now, I did some research into the smallest and largest weapons ever built, based on calculations from a ground burst. Should a nuclear weapon detonate in the air (air burst), both of the weapons described below would have a larger radius. So just … let that sink in after you’ve read the details.

And if you want to play with nuclear bombs on a theoretical map, make sure you check out NUKEMAP by Alex Wellerstein. It’s brilliant fun! In a sadistic kinda way…

Smallest nuclear weapon

The smallest nuclear weapon is not exactly going to be the source of any post-apocalyptic fiction. The M-29 Davy Crockett Weapon System was a tripod-mounted recoilless gun and developed in the 1950s for US use. It fired a bomb with a yield of about 10-20 tons, which if fired at the Auckland War Museum (sorry Auckland War Museum), would consume maybe half of the Domain in lethal radiation. The building itself would be evaporated, and anyone within a 120-metre radius would die instantly from the air burst (not to mention thermal burns or the nuclear fallout…).

Largest nuclear weapon

By comparison, the largest nuclear weapon tested was by Russia, and it’s known as the Soviet RDS-220, nicknamed Tsar Bomba (by the West). At 100 megatons, it’s even bigger than our friend the Satan-II missile (40 megatons), which I wrote about recently.

If we were to drop the Tsar Bomba on the Auckland War Museum, the radiation would extend down to just near Mount Wellington.

Now, if we were to drop the Tsar Bomba on the Auckland War Museum (so sorry, Auckland War Museum), things are very different. First, the radiation would extend down to just near Mount Wellington, and at 500 rem, that’s a 50-90% fatality rate. Except you won’t have to worry about a slow death, because the initial fireball will extend past Mount Wellington, and good luck surviving that. But even if you have your very best fire-proof suit on and you’re pretty tough, bro, the air blast will knock you at 20 psi overpressure all the way to Pakuranga.

If you’re outside of this zone, don’t worry – you’re still nice and fucked. A 5-psi overpressure blast will theoretically extend all the way down to Manuwera – and that’s still strong enough to destroy most residential buildings and kill a human being.

Now, let’s say you live in Warkworth – 61.7 kilometres from ground zero. NOPE. Still fucked. The thermal radiation radius will theoretically scratch at the southern side of Wellsford, and even that far from Auckland War Museum (so, so very sorry, Auckland War Museum), you risk third-degree burns so severe, you won’t feel them.

…because your nerves were all destroyed.

So: How many nukes to wipe out New Zealand?

Let’s assume that the supervillain behind the scheme to wipe out NZ is using one of the United State’s most common intercontinental ballistic missile (ICBM) nukes, the W-78. It seems a little tiny compared with the Tsar Bomba, but its 335-kiloton yield is still nothing to scoff at (especially if you’re under it).

Simple maths suggests that with a landmass of 268,000 kilometres squared and a ground blast radius of 37 kilometres squared (not counting the thermal radius, just what causes destruction), you would need ~7,243 W-78 nuclear bombs to completely eliminate New Zealand.

Mountains would pose a significant problem to the equation – especially the Southern Alps.

However, mountains would pose a significant problem to the equation – especially the Southern Alps. If a 335-kiloton blast were to go off in Queenstown, you likely wouldn’t notice much in Te Anau – you’d see a flash, maybe a puff of snow at the top of the mountains, but most likely not a mushroom cloud due to the sheer height of the peaks.

So, whoever wants to blow up NZ will need to consider that in their horrible plot – as much as our brilliant Southern roads are horrible for cars, they winding gorges and tricksy mountains will present a challenge for bombs, too.

Lucky us.

…I’m moving back down to the South Island and hiding in a mountain shelter…

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