verb/de.fɛʁ.le/
to break; to break out, to surge, to rise up, to sweep; to unfurl (sails)
“Municipales 2020 : une vague verte historique déferle sur les grandes villes françaises [title]” — Municipal elections 2020: a historic green wave is sweeping across major French cities
From dé- + ferler, literally “to unfurl”.