74, I believe that if you are not close to Yellow stone and you are a prepper that has saved about two years of food you have a chance at making it. You would need to have saved seeds to plant after. But I would think 90 to 95% would die just as if an EMP attack. The difference is no sun light and it will be real cold. And EMP attack or cyber attack people will still die of hunger but there will be a lot more crimes and killings.