Describing an atomic explosion as being "somewhat noisy." A statement which, while technically accurate in a strictly literal sense, fails to convey the magnitude of the situation being described. There are many ways to use this trope. One common way is following the Rule of Three by having two strongly made points followed by something more casual. It may help to have a Deadpan Snarker who habitually presents things in the least exciting manner. The Ditz may make understatements unintentionally. British and Australian humor occasionally demonstrates this.