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☢ Nuclear Blast Sequence
Interactive Timeline Calculator
Yield (Weapon Size)
15 kt (Hiroshima)
50 kt (Tactical)
100 kt (Small)
150 kt (Hiroshima x10)
250 kt (Medium)
350 kt
500 kt (Typical Strategic)
750 kt
1 Mt (Megaton)
1.5 Mt
2 Mt
3 Mt
5 Mt
8 Mt
10 Mt
15 Mt
20 Mt (Large Thermonuclear)
25 Mt
30 Mt
40 Mt
50 Mt (Tsar Bomba Scale)
Burst Type
Air Burst (Optimized for Blast)
Ground Burst (Heavy Fallout)
Distance from Ground Zero
0.5 km (0.3 mi) - Ground Zero
1 km (0.6 mi)
2 km (1.2 mi)
3 km (1.9 mi)
5 km (3.1 mi)
8 km (5 mi)
10 km (6.2 mi)
15 km (9.3 mi)
20 km (12.4 mi)
30 km (18.6 mi)
50 km (31 mi)
80 km (50 mi)
100 km (62 mi)
150 km (93 mi)
200 km (124 mi)
Wind Position
Upwind (Minimal Fallout)
Crosswind (Moderate Fallout)
Downwind (Maximum Fallout)
Shelter Quality
No Shelter - Outdoors (PF 1)
Vehicle (PF 2)
Wood Frame Building (PF 3)
Brick/Concrete Building (PF 10)
Brick - Interior Room (PF 15)
Brick - Improvised Shielding (PF 20)
Basement - Standard (PF 40)
Basement - Improvised Shielding (PF 100)
Basement - Heavy Shielding (PF 200)
Deep Underground/Bunker (PF 1000)
Wind Speed
Light (5 mph / 8 km/h)
Moderate (15 mph / 24 km/h)
Strong (30 mph / 48 km/h)
Very Strong (50 mph / 80 km/h)
Current Scenario Parameters
Lethal (Instant Death)
Extreme (Fatal without shelter)
High (Serious injury likely)
Moderate (Injury possible)
Low (Caution required)
Survivable (With precautions)
⚡ Blast Sequence Timeline
Time
Event
Effects at Your Location
Required Action
☢ 7-10 Rule for Radiation Decay
For every 7-fold increase in time, radiation decreases by 10x
1 hour after blast: 1000 R/hr (baseline)
7 hours: 100 R/hr (1/10th)
49 hours (~2 days): 10 R/hr (1/100th)
2 weeks: 1 R/hr (1/1000th)
Stay sheltered minimum 48 hours if possible
🏠 Protection Factor by Shelter
Outdoors: PF 1 (no protection)
Vehicle: PF 2 (50% reduction)
Wood frame house: PF 2-3
Brick house (1st floor): PF 10
Brick house (basement): PF 20-100
Concrete building (center): PF 50-200
Underground bunker: PF 1000+
💀 Radiation Exposure Effects
<25 rem: No observable effects
25-100 rem: Minor blood changes
100-200 rem: Nausea, fatigue, reduced immunity
200-400 rem: Severe illness, 50% fatal without treatment
400-600 rem: 50-90% fatal within weeks
>600 rem: Usually fatal within days
>1000 rem: Fatal within hours
🌡️ Thermal Effects by Distance
Thermal flash travels at speed of light
1st degree burns: Mild, heals in days
2nd degree burns: Blistering, painful
3rd degree burns: Full thickness, requires surgery
White/light clothing reflects thermal pulse
Dark clothing absorbs heat - higher burn risk
Any solid object provides significant protection