What is Plan B for Voting in America?

As we saw in Florida in the November election, there are times when due to hurricanes, or other natural disasters voters simply cannot get to the polls. Beyond natural disasters, there may be attacks or threats of attacks at polling places that create such fear and uncertainty that voters are not comfortable voting in the polls. As an elections community, federal, state and local elections officials and voting tech providers need to begin thinking about a Plan B for voting. If voters cannot or will not, go to the polls due to fear or physical limitation what is the plan for voting? Assuming State and local officials cannot randomly change Article II of the U.S. Constitution, do we have a Plan B for voting? Time to start thinking about it?