Fidel Castro once called Cuba’s power plants “prehistoric.” But the country still relies on them, contributing to the longest blackout since the collapse of its former patron, the Soviet Union.

Tropical Storm Oscar is making it harder to restore power in Cuba after a massive, prolonged power outage that preceded the storm. Oscar is hitting a key region for power generation where at least two important power plants in the city of Holguín Santiago de Cuba are located.

Hurricane Oscar made landfall on Sunday evening in Cuba, where residents were preparing for more chaos and misery as the country grapples with a nearly nationwide power outage that is