'Normal life has disappeared': Russia's energy offensive plunges Ukraine into dark and bitter cold

Major Ukrainian cities are now regularly thrust into darkness by rolling blackouts affecting hundreds of thousands -- sometimes even millions -- of people.

LONDON -- The cacophony of war has become familiar to the residents of Ukraine's major cities after nearly four years of Russia's full-scale invasion.

Each night brings the beep of air raid alerts from smartphones. Later comes the low buzz of Russian attack drones, the crackle and thud of machine gun fire from mobile defense teams, the tearing whistle of Moscow's ballistic missiles and the roar of interceptors fired to meet them.

This winter, the citywide hum of thousands of generators has dominated the soundtrack -- a "modern symphony," as Ivan Stupak, a former officer in the Security Service of Ukraine, described it to ABC News from Kyiv -- as Ukraine withers Moscow's attempt to collapse the national energy grid.

Major cities are now regularly thrust into darkness by rolling blackouts affecting hundreds of thousands -- sometimes even millions -- of people, amid heavy snow and temperatures well below freezing.

Ed Ivashchuk -- originally from the occupied eastern city of Melitopol and now living in Kyiv's southeastern Darnytskyi district -- said it is "a horrible feeling to go to bed wearing warm clothes, covered with several blankets, and still feel cold."