When there is a fire, it inevitably blazes up. However, there are many colorful words to describe this occurrence. Bonfire and inferno both describe a blaze up, as do ignite and kindle. For a more intense version, use the words conflagration or holocaust. If you're looking for a more poetic description, try the phrase "flames leaped" or "embers burst into life." For a more laid-back tone, use the colloquialism "fire up" or "start a fire." No matter what synonym you choose, a blaze up will always be a sight to behold.