Warnings of catastrophic flooding and disruption hamper the US presidential campaign as Hurricane Sandy sweeps down America's east coast.

Hurricane sandy warning (reuters)

It could be the October surprise that everyone's been waiting for: out of nowhere, what's expected to be one of the most violent storms ever to hit mainland America. It has sent tens of millions of people across the Eastern seaboard scrambling for emergency supplies, evacuating low-lying areas, and preparing for the worst.

Forecasters are predicting winds of between 60 and 80 miles an hour, enough to topple trees, loosen glass in high buildings and cause widespread flash flooding. Walking through city streets, they warn, will be "difficult and dangerous": driving conditions are likely to be treacherous.

Read more: US braced for 'Frankenstorm'

Already hundreds of thousands of people in lower Manhattan are being evacuated, the city's underground system will be shut down at 7pm, schools are being closed and some 2,500 flights will be cancelled.

The best thing we can do is focus on how we can help people during this storm. David Axelrod, Obama chief strategist

Although the hurricane is expected to hit land in New Jersey, the resulting storm will affect a vastly wider area, including the nation's capital Washington DC. In the city this morning, residents were taking advantage of the still-dry conditions to stock up on food, water and wet weather gear.

In the trendy Dupont Circle branch of Whole Foods Market, the queue snaked around the store, as people rushed to buy essential supplies of organic arugula.

It is not just daily life that is being affected. The impending storm has thrown the election campaign schedule off kilter, as the candidates hastily reorganised their travel plans.

Rallies scrapped

Mitt Romney cancelled an election event in the swing state of Virginia, flying instead to Ohio to appear alongside Paul Ryan. President Obama will leave for Florida tonight, fitting in a campaign rally in Ohio on the way back to Washington on Monday to monitor progress of the storm.

A joint rally which Obama had planned with Bill Clinton in Virginia on Monday has been scrapped, along with plans to travel to Colorado on Tuesday: two more crucial swing states where every appearance by the candidates could be critical.

Virginia's Democratic senator Mark Warner, who was supposed to appear at the Obama/Clinton rally told Fox News: "The storm will throw a little bit of havoc into the race," although he was confident that it would not prevent his constituents from going to the polls.

The White House said the president was being briefed constantly on the hurricane's advance, while the authorities prepare "to bring all available resources to bear" in the worst affected areas.

And his Chief Strategist David Axelrod promised: "The best thing we can do is focus on how we can help people during this storm and hope that it all clears out and that by the next weekend we'll be free of it and people can focus on the election."

Several of the most important battleground states are in the path of the storm, including North Carolina, Ohio and Virginia, prompting fears that it could affect voter turnout, especially in efforts to persuade people to cast their ballots early.

Path of wrath

But for the truly Machiavellian, the exact trajectory of the hurricane could even become a political advantage, according to Virginia University's Larry Sabato, in TPM:

"If Obama were directing the snowstorm it would be in the Shenandoah valley and south-west Virginia as they want as low a turnout as possible in those rural areas. If Romney were directing the snowstorm, it would go right down the corridor from Northern Virginia into Richmond, which is where Obama's votes come from.”

The same holds true for Ohio, where snow or storms in the north-west could affect early voting for the Democrats, whereas if rural areas are hit, that could dent Republican support.

Whatever you make of the candidates' qualities, though, they're certainly not capable of controlling the weather. Yet. But it isn't just campaign events that are affected: opinion pollsters are also warning that they won't be going out to canvass voters in extreme weather.

As yet, no-one can predict how far the monster storm surge will affect the outcome of November's vote. At the moment, the priority is making sure that the millions of people who are potentially in its path, remain safe.

Felicity Spector writes about US politics for Channel 4 News