The resident population of Manhattan is 1.63 million people. During a workday, the commuter population swells that to 3.9 million. The population of Puerto Rico 3.66 million, roughly the same as Manhattan, except it is about a thousand miles away from CONUS, in the Atlantic Ocean. You can’t get there by car or train.

The logistic problem of getting aid to the island is staggering. Even if the docks and airfields were all open, how do you get a case of bottled water from the ports to a little old lady living in, say, Arecibo?

Supplies are already piling up at the ports, ships, fully laden with emergency supplies are trying to find anchor and dock space, but there is no way to move supplies across San Juan, much less across the island. The city streets and mountain roads are impassable, fulled with debris or washed out. They need bulldozers to clear the roads, and bulldozers need fuel, and there is little fuel available, or electricity to pump the fuel that is at hand, or any way to get the workers needed to pump the fuel to their jobs. And that’s just one little old lady in Arecibo. Bulldozers need fuel. So do ships, airplanes, trucks, home generators, helicopters, police cars. Everything is interconnected and self-dependent.

In the US, families are recommended to prepare for natural disasters by keeping at least several days food and water in the house, to fill up their car with gas and to get some cash at the ATM for when the power goes out. They are asked to get batteries for their radio, their flashlights and to recharge their cell phone. It is suggested they have plenty of clean laundry and bedding on hand, the dishes are clean and that the pets are well supplied. Puerto Rico has already used that all up.

I heard on the radio today gangs of thugs are roaming PR stealing home generators at gunpoint. The apocalypse is here.

And there are other, long-term consequences:

https://slate.com/business/2017/09/what-happens-if-puerto-ricans-flee-en-masse.html