To give you an idea of how quickly much of New York City lost power consider these numbers: at the start of Monday there were six reported power outages affecting seven businesses or homes; by Tuesday evening those numbers rose to 831,138 customers (homes and businesses) affected by 12,165 outages.

But the cleanup is well under way. Utility and sanitation workers managed overnight to start bringing down those numbers. By Wednesday morning, nearly 758,000 customers were still fully or partially offline due to more than 11,000 outages.

Most city residents without heat or power are concentrated in lower Manhattan – from the Empire State Building to the New York Stock Exchange nearly four miles to the south – a densely populated swath of Gotham that could end up celebrating Halloween with candles, powered-out cell phones, emergency radios and flashlights.

While over 200,000 of these customers are concentrated in this zone and linked to flooding and explosion at the massive substation of Consolidated Edison, Inc. (NYSE:ED) in the Lower East Side, the rest of the metro area’s power problems are scattered like fall leaves across the five boroughs and Westchester County. The main culprit: branches that fell on power lines.

Thousands of sanitation and utility workers have been working to clean up these dangerous messes that pose a risk to passersby that might not be aware of the live electrical wires tangled in the fallen branches. On Wednesday morning ConEd issued a warning to trick-or-treaters and other Halloween revelers to be wary of downed electrical wires or equipment and to be visible to motorists in areas still without power tonight.