You've probably heard by now the warning people that Sandy might cause so much havoc that it will probably have an effect on Election Day. The wind, rain, snow and flooding is expected to affect power and travel for up to 10 days after it comes ashore in the middle of next week. I think the potential exists for a situation where a lot of people may not be able to vote unless they cast early ballots in states that allow it.
How might this storm affect the results? We might expect cities to be the first to get power back, and cities are generally easier to get around to local polling stations even on foot. In rural areas the power may not come on as soon. Moreover, rural areas run a larger risk of transportation disruption due to downed trees and power lines, flooding and snow. If we look at the demographics, this may mean that democratic voters in the cities may be more able to get to their polling station and will be more likely able to use electronic voting or paper voting (depending on state). This also means that Republican voters in the rural areas may have difficulty getting to their polling station and there may not be power for electronic voting if they get there, and a couple states in the affected area (Virginia and Pennsylvania) have paperless voting and may not have paper backups ready. An urban/rural storm impact divide could result in a larger number of democratic-favored ballots and give that party the edge in the elections.
What can be done? People could vote early, if their state allows it, although it may be too late for that depending on hours available over the weekend and how soon the storm starts affecting the region. The election could be postponed, but that would take an act of Congress. However with potentially more Republican voters being affected, the Republican majority House may choose that path... if they have enough time to convene in Washington (or elsewhere?) before the storm affects DC.
It's also not clear if changing the election would be legal this close to Election Day. I don't know if states can attempt late voting since the constitution demands a single election day to be the same across the nation, but if early voting is allowed by law, then perhaps late voting can be as well since delays in certifying the election are normal and considered legal. However, some jurisdictions in the affected region will probably not be able to make any changes to their voting rules due to the requirements of the Voting Rights Act of 1965, including most of Virginia (a double-whammy with paperless voting), all of South Carolina, parts of North Carolina, a lot of New Hampshire, and parts of New York City (Manhattan, Brooklyn, the Bronx) unless they receive preclearance from the US Justice Department, which may or may not be coming. Perhaps they will offer preclearance retroactively, or maybe Congress will step in directly... if the majority thinks it will be to their party's advantage.
Alternately, the State Legislatures or the Governor may appoint Electors directly, according to the various state's own constitutions and laws since the US Constitution does not require that electors be directly elected. Thus, the disaster and related states-of-emergency or martial law might be used as an excuse to discount the election and appoint electors for whichever party controls a state's necessary organs for appointment of Electors. However, in either event, the Electors themselves have to bear the decision as to whether they shall remain faithful to their party or if they shall be a faithless Elector and vote their conscience on their own beliefs, including the validity of the general election and the wishes of the voters and the potentially disenfranchised. One could say that this sort of exigency justifies the continuation of the Electoral College process, but I suppose that will depend on how fair the result turns out to be.
Or the Supreme Court of the United States may jump in, again.