Energy Providers Warn Rolling Blackouts Still Possible Wednesday As frigid temps continue to keep this area in a proverbial polar vortex stranglehold, power providers are preparing people for the potential of additional rolling blackouts again today. Dakota News Now is reporting the power blackouts experienced on Tuesday (February 16) by many residents throughout the eastern half of South Dakota were lasting between 30 and 90 minutes in most cases. Energy providers are strongly encouraging people to once again conserve and limit energy usage when possible to help ease the burden being placed on power grids at this time. Get our free mobile app