UPDATE: The Texas DPS says in a PDF that only 2.87 million customers were without power at the peak of the outage (thanks blog reader Phillip from Entergy). This brings into question the WikiPedia number of 4.5 million. That number was from this Bloomerg article, and quoted "cutting power to at least 4.5 million people in the Houston area." How they got this number is a mystery, and they could have been using an equation to calculate the number of people per "customer." The U.S. Department of Energy also put the estimates for Isabel outages [PDF] at only 5,000,000. The DOE also says that the maximum number of people without power at any one time was 3.8 million [PDF] but their numbers don't say how many lost power altogether. If you look at their reports, this is what you come up with for "max # of customers out per state":

TX: 2,878,000 OH: 1,084,000 KY: 472,000 LA: 219,000 AR: 154,000 IN: 111,000 PA: 60,000 IL: 0 NY: 0

Obviously Illinois and New York are missing, which is a problem, and PA is too low considering that I saw 65,000+ on Alleghany Power's website myself. The DOE disclaimer says "due to a large number of service providers, including investor owned utilities and cooperatives, the number of customer outages reported may not be comprehensive." But, for the record, the DOE total is 4,978,000, which is close to, but less than, their Isabel estimate.

During my power outage last night, I asked myself the question: How many people did Hurricane Ike rob electricity from, all totaled in his trek from Louisiana and Texas through Pennsylvania and New York (when, technically he was no longer a Hurricane but just a low pressure with high winds, still causing power outages)? I did some research, then some editing over at the WikiPedia entry, (and also confirmed their numbers). If my math is correct, the number is over 7.5 million (7,550,000 to be specific).

Given that power is reported by separate power companies, which only cover small areas, this number if probably underestimated (for example, the only number we have for Kentucky is the Louisville area, the number is probably closer to 8 million. Here's the breakdown, where I have also noted historical subtext (all references are in the WikiPedia entry):

Texas: 4,500,000 Ohio: 1,591,000* Indiana: 350,000 Kentucky: 300,000 (Louisville) - UnprecedentedLouisiana: 200,000 Arkansas: 200,000 - Worst Since 2000New York: 100,000 Pennsylvania: 180,000 (Western)Missouri: 85,000 Illinois: 49,000

According to WikiPedia's list of major power outages (which I just added Ike to, take THAT, WikiPedia editors!), this ranks as largest outage since the Northeast Blackout of 2003. It also was the largest Hurricane-related outage, though their list was clearly incomplete. They also didn't list Isabel, which knocked out 6 million, or the Blizzard of 1993 / Storm of the Century, which caused over 10 million to lose power. I think it's possible this is the largest weather-related power outage since then.

If you remember any power outages on this scale, especially ones that WikiPedia is not already listing, leave me a Comment below.