... or, How I learned to Stop Worrying

@Mazura indeed, and that was before ICBM and multiple warheads.

Ionizing radiation only propagates further out than blast and heat for extremely small (think sub-kiloton) nukes. Above around a kiloton, blast is lethal further out than radiation, and, beyond 100 kT or so, thermal radiation is lethal further out than both. And a nuke targeting a city will be an airburst, which produces no significant fallout - just prompt radiation from the fireball itself, which can be rendered survivable by a meter and a half of water shielding (whether the water will shelter you from the blast and heat is another matter).

@Vikki The blast in Hiroshima was about 16 kT, resulting in about 150,000 deaths from the blast alone, half of them killed instantly.

@RogerVadim: Were you trying to disagree with any part of what I said?

@Vikki I am simply not sure about the point that you are trying to make. Are you disagreeing with something that I had said?

@RogerVadim: I was disagreeing with the "Penetrating radiation propagates much further" and "one will be left to die more or less slowly from the radiation sickness" parts of your answer, both of which are demonstrably wrong.

@Vikki The phrase about penetrating radiation was mainly to address the answer by at_foolishmuse, which considers it as the only (or the main) effect of an explosion. If you can propose a good formulation, I am ready to modify my answer. If you simply want to tell me that I am wrong - I have heard you.

> in the case one survives the explosion, one will be left to die more or less slowly from the radiation sickness. My philosophy is to keep a weapon around in case you're unlucky enough to not die instantly.

@Mazura - Thank you, Doctor!

"not enough time to jump on a bike." The question hypothesises that there is 16 minutes warning before the bomb detonates.

@SteveIves The first sentence in the answer addresses this premise. The following paragraph however deals with what happens after the explosion, addressing the unrealistic assumptions like jumped off my bike into the canal with ballast as soon as the buildings around me light up due to the explosion.

+1: It's quite interesting that people continually underestimate the first order effects of a catastrophic situation and focus on mitigating the higher order effects. A similar question about surviving a tsunami was recently asked in a subreddit and the OP focused entirely on building an underground structure that water won't pour into once the place is flooded but completely ignored the sheer impact of the tsunami.

@RogerVadim Good point but then you should have written 'jumped OFF a bike into the canal' instead of 'Jumped ON a bike', which implies you are referring to getting out of town when the warning sirens go off.

"A few km" depends on the weapon. Some nukes, yes - others no. There are much smaller weapons with much smaller blast radii. Also, at a few km distance the shockwave doesn't hit for at least a few seconds. The heat and radiation hit instantly, at the speed of light, but if you're sheltered from the initial flash you do have a few seconds, depending on how far you are, to take cover before the shockwave hits. Surviving the first hour is the most critical.

@RogerVadim I need 3 seconds to react to the flash, swerve into the canal, & dive. How far out would the shockwave be 3 seconds after the beginning of the flash? (I have time to get to 4.4 miles out because the sirens sound not in response to radar warning, but rather a live televised speech by the adversarial leader attempting to justify to his enemies & his people why he has just given the order to launch, before he & they are annihilated. The warhead headed my way is the 600th of 1200 deployed to launch after hesitation by its crew, & arrives 25 minutes following the start of the speech.)

@Tom It will all happen at subsecond speeds. The heat wave is actually radiation propagating with the speed of light - have you heard about shades in Hiroshima? Also, I wouldn't bet on a warning by an adversarial leader... however, approaching ballistic missile will be probably detected within somewhere between a few minutes to a few dozens of minutes. Of course, you have to trust that the sirens in your city sound alarm - are they regularly tested?

@RogerVadim , I am unable to deduce from online footage of nuclear explosions that this would happen an subsecond speeds, could you provide a link to a graph showing the progress or speed of a shockwave vs time? Ideally for approximately a 1Mt explosion.

@Tom Online footage is done from which distance?

@RogerVadim Most of our sirens system is dismantled, though I'd hope if nuclear tension rise more sirens will return to use/testing. Hopefully direct radiation at 4.4 miles would be initially blocked by buildings. Would direct radiation at this distance burn through the hood of my outdoor jacket within 2 secs? I'm naive but the simulator I used said only 1/2 my city's population would be killed in a 1Mt explosion, I prefer to be in the other half, but if nuclear threats/brinkmanship reached a certain tempo, I'd actually return to my parents, who live in a mountainous, sparsely populated region

@Tom Keep in mind that the likelihood of megaton bombs going off is extremely low. Putin and his whole chain of command would basically be in a murder/suicide pact at that point. The real threat of this war that nobody wants to talk about is normalization of tactical nuclear weapons in land war. Obviously the US isn't going to flatten every Russian city with ICBMs if Russia decides to start cracking off small tactical nukes. What nobody wants, though, is pandora's box to be opened - once tactical nukes are on the table for normal war then everything changes about war. Forever.

@Tom And if you really want to sleep well... Russia has a 10:1 advantage in tactical nuclear weapons over the US.

@J... Tactical nuclear weapons would fit with Russia's current 'escalate to deescalate' nuclear doctrine (which I think is a contribution of Putin's?) See images of 'Grozny destroyed'/'Grozny 2000' to see what he's capable of even on home soil (2nd Chechen war started after he became PM and escalated after he became president.) As soon as this current Russian doctrine results in a warhead hitting any nuclear-armed country as a "warning" I'm heading for the hills. Hope he & his massive pride complex could handle losing the Ukraine war, & that it wouldn't heighten his sense of feeling cornered.

@RogerVadim see "The Effects of Nuclear Weapons" (Samuel Glasstone, 1964), page 89, which has a diagram suggesting a shockwave from a 1Mt airburst would take 11 seconds to reach a radius of 3 miles. archive.org/details/TheEffectsOfNuclearWeapons/page/n30/mode‌​/…