A common variant of dump, the powerdump often occurs when one has diahrrea, has eaten something just a little too spicy, or has held it in just way too long. According to extensive reasearch on the powerdump, the majority of people who undergo it often say that it is one of the more unpleasant kinds of dumps. When taking a powerdump, it is not unusual to firmly grip the underside of the toilet seat to maintain stability.
Man, Rick had to take a powerdump last night, and he ended up spewing crap all over the place before he could sit down. Now my bathroom's ruined.