flare up

ignite quickly and suddenly, especially after having died down

• “the fire flared up and died down once again”

erupt or intensify suddenly

• “Unrest erupted in the country”
• “Tempers flared at the meeting”
• “The crowd irrupted into a burst of patriotism”

a sudden violent happening

• “an outburst of heavy rain”
• “a burst of lightning”