flare up

Verb	1.	flare up - ignite quickly and suddenly, especially after having died down; "the fire flared up and died down once again"
	2.	flare up - erupt or intensify suddenly; "Unrest erupted in the country"; "Tempers flared at the meeting"; "The crowd irrupted into a burst of patriotism" Synonyms: erupt, irrupt, break open, burst out, flare

ignite, inflame, kindle, light