a sudden violent happening; "an outburst of heavy rain"; "a burst of lightning"

Any sudden acceleration of wildfire spread or intensification. Unlike a blowup, a flare-up lasts a relatively short time and does not radically change fire-management plans.

Any sudden acceleration of fire spread or intensification of a fire. Unlike a blow-up, a flare-up lasts a relatively short time and does not radically change control plans.

Clumps of fuel or single trees that are consumed by fire rapidly and then die down, and do not constitute spread through the crowns.

Any sudden acceleration of fire spread or intensification of the fire. Unlike blowup, a flare-up is of relatively short duration and does not radically change existing control plans.

when the rectum and/or colon become inflamed. During a flare-up, people experience periods of increased symptoms of ulcerative colitis, such as bloody diarrhea, rectal bleeding, abdominal pain or cramping, and an urgent need to have a bowel movement. Flare-ups can vary in duration and intensity.

Period of worsening symptoms

An increase in clinical disease symptoms.