Florida and Texas have been battling it out since the beginning, but Texas has always managed to start and end strong by operating with literally the most unreliable and expensive energy distribution infrastructure/grid in these United States while it's extraction infrastructure is an unsafe Byzantine network of pipelines vying to create another Biggest Spill in History at any moment.
it's a dice role of meteorological forecasting, but I am betting the most extreme mass casualty event to kick off the official climate apocalypse (North America edition) is gonna be Texas, because they are not going to be able to keep people warm or cool for a critical period of time during some phenomenon.