 Bloomberg -- After Hurricane Sandy plunged much of the New York region into darkness in 2012, local electric utilities spent more than 3.5 billion to ensure it wouldnt happen again.And yet, one week after Isaias roared through, more than 40,000 New York-area customers remained without power. Over 1 million homes and businesses were still in the dark as late as five days after the storm. Why?The short answer: Utilities girded for another Sandy. They got Isaias instead.While New York-area power providers have funneled billions into protecting their infrastructure from the storm surge and flooding of a Sandy, they say theres only so much they can do against the wind gusts of an Isaias, which can tear down mature trees and snap utility poles.That means occasional, lengthy blackouts could become the new normal for New Yorkers, particularly as storms grow both more frequent and more severe due to the warming climate.These major storms slamming trees and limbs and other debris into pieces of infrastructure are going to cause outages, said Jon Wellinghoff, former chairman of the Federal Energy Regulatory Commission and the founder of GridPolicy Consulting. Theres no way to avoid that.Isaiass rampage through the Northeast initially left more than 2 million homes and businesses without power, becoming one of the worst storm-related outages since Sandy, which blacked out almost 5 million customers in New York State and New Jersey. As of Wednesday, more than 16,000 outages remained, mostly in Nassau, Suffolk and Westchester counties in New York State and Connecticuts Fairfield County.About 700 miles to the west, over 600,000 families and businesses were without electricity for a third day after deadly winds cut a path of destruction across Iowa, Illinois, Wisconsin and Indiana Monday.Read More: One Million Lost Power in Storm That Spawned Chicago TornadoThe New York-area utilities maintain the money theyve spent strengthening the grid in recent years helped them restore service faster than they could have otherwise. But public officials -- and a few utility executives -- say the companies underestimated Isaias, failing to have enough workers on hand to launch into repairs once the fast-moving storm cleared the region.One utility, Consolidated Edison Inc., had to fly in reinforcements from other states after the fact. Governor Andrew Cuomo labeled the companies response a lousy job, while a Connecticut lawmaker suggested breaking up one of the utilities, Eversource Energy, saying it had grown too large and unfocused to provide reliable service.The companies post-Sandy upgrades, paid for by their customers, have drawn criticism in the aftermath of Isaias.It doesnt seem like a good investment, Connecticut Public Utilities Regulatory Authority Chairman Marissa Gillett said Friday. Theyve spent hundreds of millions of dollars on improvements and ratepayers deserve to know where that money went.Post-Sandy InvestmentsAfter Sandy, ConEd spent more than 1 billion on grid resilience projects through 2016, according to spokesman Allan Drury. That included flood walls and water pumps for substations as well as systems for containing blackouts in Lower Manhattan so they dont spread to more of the city. The company has performed similar work in Westchester County, installing switches that can isolate a power outage and cut the number of people affected by 75 when a tree falls over a wire. It spends about 1 billion on grid upkeep each year.Public Service Enterprise Group spent 1.2 billion over five years to shield both its electricity and gas systems in New Jersey from flooding. The company has raised, relocated or reinforced 26 substations and switching stations in flood-prone areas, according to spokesman Michael Jennings.In Connecticut, Eversource Energy has been allowed to spend over 660 million under a infrastructure hardening plan that was approved in 2013. In July, the company said its spending 83 million this year trimming branches and cutting trees along 4,200 miles of roads -- work that can pay dividends during storms like Isaias. Yet, some of its customers were still in the dark seven days after the storm hit. In New Jersey, Jersey Central Power Light spent about 1 billion in its grid infrastructure since 2016.Theres not really a magic bullet to protect us at this point from having damage to our equipment in the face of such storms, JCPL spokesman Clifford Cole said.Too Few WorkersJames Slevin, president of the Utility Workers Union of America, said the long outages are a sign that utilities dont have enough workers for maintenance and are relying too heavily on outside aid. ConEd, for example, had 1,650 employees on repair work last week. They were eventually joined by about 2,000 mutual aid and contract workers from such distant locals as Florida, Texas and Wisconsin.They rely on mutual assistance and contractors and theyre spread so thin they dont have the people to put up the wires, Slevin said. Its getting worse.New York state regulators are investigating the matter. Our initial review is that more resources were needed, said James Denn, a spokesman for the New York State Department of Public Service, in an emailed statement.One way to minimize wind damage would be to bury power lines underground, but thats extremely costly. Instead, utilities can take steps such as sectionalizing grids so that blackouts can be more easily contained. Installing more distributed power generations sources and microgrids can also help.Short of those changes, it may fall to homeowners to take care of themselves. Wellinghoff, for his part, lives in California, where the utilities have started shutting off power during windstorms to prevent fires. Hes about to have two Tesla Powerwall batteries installed at his home, to go with his 8-kilowatt rooftop solar array.Updates outage figures in 8th paragraph, adds JCPL comment in 16th.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 