When a nuclear warhead is detonated it generates a blast wave that can destroy objects up to dozens of miles away. It is important to know how close you are to major nuclear war targets, which I have posted here as well. If you know the distance from these targets and the type of target you can figure out what type of overpressures your area will experience. It is important to know if the target is a hardened target or soft target because this will determine if the enemy will use a surface burst or an air burst. Typically surface bursts are used against hardened structures while air bursts are used against soft targets such as cities and bases. Air burst warheads have a larger but weaker blast radius, while surface bursts concentrate the blast radius and very high overpressures closer to the flashpoint.
The blast wave travels at the speed of sound the first few miles then starts to slow down, which means you have seconds to take cover behind a hardened object or get below-grade. You will want to get away from exterior walls if inside a structure, due to flying debris and the blast wave itself which may destroy them. This is why the duck and cover drills were created. Move to the interior portion of a structure, jump into a ditch or culvert or depression in the ground, get behind a hill, get behind a sturdy object that won't get blown over (vehicles are not good), or go underground. Remember you will only have SECONDS to do this once the warhead is detonated, don't be picky. If our early warning radars and satellites detect an ICBM launch you should have 15-30 minutes MAX before detonation. Have several blast shelter locations near your primary residence, any secondary/tertiary residence, and your place of work. Basically any area you spend a lot of time in you should have several blast shelters planned out, those that you can reach in seconds if you don't get notified of ICBM launch and those that you can reach in under 15 minutes if you are notified.
A nuclear weapon can actually have two blast waves, the main blast wave and the reflected blast wave. This usually only happens with air bursts when the main blast wave reaches ground level the earth will create a secondary blast wave as the main blast wave reflects off of the ground. At some point the main wave will catch up with the reflected wave as it is travelling faster, but this doesn't happen until some distance from the flash point. Therefore within a few miles of the flash point there will actually be two blast waves. Further from the flash point the merged main and reflected wave will impact objects as one big wave.
Be aware also of the negative portion of the blast wave, just like waves at the beach that wash back into the ocean. After the positive phase of the blast wave(s) passes through an area there will be negative portion almost as powerful as the positive phase. The negative phase may take longer so remain sheltered after the positive phase passes, wait for the negative phase to pass.
1 psi = 38 mph wind
5 psi = 163 mph wind (50% chance of eardrum rupture)
10 psi = 294 mph wind
20 psi = 500 mph wind
8 psi - wood/brick structures start to collapse.
30 psi - Lungs collapse
Light Damage Zone (LDZ) 1-5 psi - flying glass, debris carried by the blast wave, damage can vary as blast wave is reflected in different directions by buildings and terrain. Most modern nuclear weapons - 10 miles + from the flash point.
Moderate Damage Zone (MDZ) - 5-20psi - substantial damage, but not total destruction. Most lightly built structures (stick frame) will collapse totally or partially. Sturdy structures made of reinforced concrete or block will be intact (main difference between SDZ). Overturned cars, firestorms, caved in roofs, blown out interiors, telephone/light poles blown over, gas lines/gas stations may get damaged from the blast wave threatening fires and explosions. Most modern weapons - 2-10 miles from the flash point.
Severe Damage Zone (SDZ) - 20 psi+ - Think Twin Towers after 9/11, total collapse of most buildings including sturdy structures made of reinforced concrete. Few people expected to survive. Rubble will be impassable. Severe fallout radiation. Fatal initial radiation. People in subterranean structures may survive - subway tunnels, underground parking garages. Most modern nuclear weapons - 2 miles or less from the flashpoint.
Blast and Heat radii for commonly deployed nuclear warheds:
5 megaton Dong-Feng 5 Chinese ICBM currently deployed - to take out cities and capitol
Fireball radius: 1.84 km / 1.1 mi
Moderate blast damage radius (5 psi): 12 km / 7.2 mi
Thermal radiation radius (3rd degree burns): 24.5 km / 14.7 mi
light blast damage radius (1 psi): 33.8 km / 20.3 mi
800 megaton Topol M Russian ICBM - to wipe out larger targets like larger bases, big cities, or large bunkers
Fireball radius: 0.97 km /0.6 mi
Moderate blast damage radius (5 psi): 7.03 km / 4.2 mi
Thermal radiation radius (3rd degree burns): 12.2 km / 7.3 mi
Light blast damage radius (1 psi): 19.8 km / 11.8 mi
300kt MIRVed warhead used by Russian RS-24 Yars, most likely used for hitting silo’s and small-medium sized targets. Keep in mind many warheads can be detonated to overlap blast waves to create a larger damage radius or two can be used for one hardened target to ensure destruction, such as for hardened silos in the Midwestern U.S.
Fireball radius: 0.6 km / 0.3 mi
Moderate blast damage radius (5 psi): 4.71 km / 2.8 mi
Thermal radiation radius (3rd degree burns): 7.17 km / 4.3 mi
Light blast damage radius (1 psi): 13.2 km / 7.9 mi
150kt MIRVed warhead used by Russian SLBM's and ALCM's - most likely used for very small point targets like silos and smaller bases
Fireball radius: 450 m
Moderate blast damage radius (5 psi): 3.74 km / 2.2 mi
Thermal radiation radius (3rd degree burns): 5.26 km / 3.1 mi
Light blast damage radius (1 psi): 10.5 km / 6.3 mi
Thank you for all your information! Best wishes with your problems with YouTube and the rest of the naysayers!