The Pentagon is developing FORTRESS, a program that would require each major base in the 48 contiguous states to operate independently for at least 90 days if war severs the commercial electric grid and supply chains. The requirement would cover water, fuel, communications and power. The Pentagon has not identified the adversary it is considering, but U.S. cybersecurity, intelligence and law enforcement agencies warned in 2024 that Chinese state-backed hackers had breached American energy, water and communications networks, potentially positioning them for disruption during a future conflict. The U.K. launched its Be Ready campaign on Oct. 22, advising families to hold three days of water, shelf-stable food and cash if essential services fail. Wealthy households have pursued similar resilience measures for years, including generators, remote second homes, supply stockpiles and underground shelters. Advisors and agents told Fortune that demand has increased in recent years, with concerns ranging from infrastructure outages and hurricanes to physical security.