I'm trying to construct a society which has had a narrow miss with a natural disaster that has isolated them, scared them considerably, changed the culture, made many of them preppers, but didn't kill many/any of them. But I'm struggling to build a setting which has the right level of destruction, isolation, and fear without wiping the city out.
I'm looking to know if its at all possible for a natural disaster that:
- Completely isolates a large, modern, first-world city from the rest of the world.
- By large I mean 1 million people plus. 200 square miles plus.
- Eg LA, Chicago, Houston, Phoenix, San Diego, etc.
- Forces the closure of all travel and freight into and out of that modern city. Road, rail and air are totally stopped.
- No food.
- No medicine.
- No gasoline.
- No mail.
- That lasts for at least 3 weeks,
- Even with an effective emergency service giving a 100% response inside in attempting to get out.
- Even with outside world giving a 100% response to attempting to get inside and help.
- Even with multiple levels of functional, funded, non-corrupt government doing mostly the right things.
- Even with a cooperating public following all the instructions.
- (if possible) cuts satellite uplinks.
- (if possible) prevents air drops of supplies.
- (if possible) directly kills as few people as possible, and leaves the city mostly livable after it passes.
- (if possible) Cuts off the internet and phone lines in and out of the town - no exchange of data with the outside world.
- (if possible) prevents satellite or recon planes from knowing people are still alive.
I know that tornados, floods, and hurricanes can blow/wash away roads, or flatten airports, but my understanding from decades of CNN is:
- Small towns (< 10,000 people) can be cut off for weeks when their only road washes away, but supplies can be airlifted in.
- Large city's (> 1 mil people) can loose a few highways to big twisters, but their full perimeter can be hundreds of miles, no disaster is big enough to wipe out all those roads on all sides without also taking out the city.
- Earthquakes can take out roads over a large area, but airdropping supplies is still possible, and non-elevated roads can be patched pretty quickly.
- Large cities can loose their airports to disasters, but that's unlikely to take out all the roads 100s of miles away as well.
- If it does occur, the runway can be cleared by heavy machinery pretty quickly.
- A big, widespread disaster, like a tsunami or hurricane, could reasonably take out all these things, but some roads could be cleared quickly, and supplies can be helicoptered / airdropped in while roads and runways are being cleared.
The best I've got is: an unrealistic meteor shower that falls in a ring-shape that manages to take out every road, rail, and pipe leading into town, but magically leaves the city intact, except for one hitting the airport, followed by a "Carrington event" that wipes out everything electronic, ceasing all communications. That's pretty unrealistic, surely I can do better than that.