With Hurricane Sandy threatening to slam the East Coast, President Obama and Mitt Romney are being forced to reconsider their strategies for the final week before Election Day. Meteorologists warn that Sandy's expected collision with a wintry storm from the west and an icy blast from Canada could create a violent "Frankenstorm" just in time for Halloween. Mitt Romney has already canceled a rally in Virginia, a closely fought swing state that is about get drenched. And the disruptions could mount in the coming days: "Sandy is a loose, unpredictable cannon," Kerry Emanuel, an MIT climate researcher, tells Politico. Here, five ways the storm could alter the endgames of both campaigns:

1. Ruin planned events
Here it is, "our October surprise," say Chuck Todd, Mark Murray, Domenico Montanaro, and Brooke Brower at NBC News. "What happens to Obama's events with Bill Clinton on Monday in Florida and Virginia?" If parts of Ohio are a slushy mess late next week, it could also derail the final blitz by both campaigns in what is being billed as the state that might tip the election.

2. Curb early voting
"President Obama needs a huge early voting turnout in Florida on Saturday, when in-person early voting begins," says Marc Caputo at The Miami Herald. It's the only weekend of early voting in the Sunshine State, which always looms large as a big battleground. If Sandy tilts a tad to the left and slows down, it could soak much of Florida with rain. "That's bad news for President Obama and good tidings for the Republicans." Sandy could also slow early voting in North Carolina, Ohio, and Virginia.

3. Distract the media
Sandy is "threatening the media epicenters of New York and Washington, guaranteeing that the networks will be in All Storm All the Time mode just as Obama and Romney are trying to make their final pitches to voters," says Darren Goode at Politico. That means less air time for networks and cable channels to "parse the details of Obama's jobs plans" or "Romney’s efforts to distance himself from other Republicans' rape comments."

4. Make voters mad at Obama
Team Obama says it doesn't think the storm will be "a major issue," says Rachel Weiner at The Washington Post. But a 2007 study in the Journal of Politics found that bad weather "generally helps Republicans" because it reduces turnout. "Better weather, the authors say, would have won Al Gore Florida in 2000." That's not the only reason for Obama to be nervous: A 2004 study shows that "acts of God, including droughts, floods, and shark attacks" cause voters to take out their frustration on government.

5. Give Obama a chance to shine — or stumble
Call it "the Katrina factor," says Goode at Politico. "Any disaster offers a chance for a president to step up and come to the aid of the public, or stumble and be regarded as a goat." If the dreaded Frankenstorm hits and Obama handles it well, he'll look like a hero. He's in trouble, though, if he repeat's "George W. Bush's lagging response to 2005's Hurricane Katrina." With the race just days away, "Obama will have little time to recover if he fails to respond properly to Sandy — or if Republicans successfully plant the meme that he failed."

Read more political coverage at The Week's 2012 Election Center.