|Consider this. The Cascadia Subduction zone registers a 9.0 Richter Scale earthquake involving the Juan de Fuca Plate. This plate extends from the middle of Vancouver Island in British Columbia, Canada down to Oregon. Seattle, Portland, and even northern coastal cities in towns in Northern CA are devastated and a huge tsunami wave hitting the west coast and Hawaii have made matters even worse. Think of the Indonesian earthquake and tsunami of Dec. 26, 2004 if you need a mental measuring stick.
The problems include all major and minor airports sustain such damage as to make them unusable in the affected areas. Landslides have made highways leading in from other states impassable, and the tsunami has wrecked naval and civilian shipping lanes and bases, not to mention the damage caused to homes, businesses and basic infrastructure from both the tsunami waves and earthquake and subsequent tremors.
The task is to get military units into the affected area - note that local forces may very well be in a bad state themselves due to their proximity to the disaster - with sufficient numbers, equipment, and supplies to get some critical air landing strips setup or repaired, and to start disaster recovery ops. The problems include not having road access due to collapsed mountainsides that have crippled railways, roads, and bridges. Airports may take days or longer to get operating.
As Chairman of the Joint Chiefs, what can you tell the President as to the logisitics of supporting 5-million or more people by airdrops - that is how many C-5's, C-17's, and C-130's would have to be used on a round the clock basis? What other methods would you recommend. ie. Having all LHA/LPD, LHD head for the westcoast?
This scenario btw, is not theory, it is actually the expected results of the equally expected 'Big One' off the westcoast of Canada and the USA.