flare

flare 1

•  verb

1    also flare up [I] to suddenly begin to burn very brightly:
?Lightning flared and flickered.
2    [I] also flare up to suddenly become worse, very angry, or violent:
?Violence has flared up again in the region.

flare 2

• noun [C]
• 

1    a thing that produces a bright flame when it is shot into the air, especially as a sign that help is needed
2    a sudden bright flame