A system and method of detecting, evaluating, monitoring events during the removal of heat from tissue beneath skin. The system utilizes an adaptive filter to determine if a partial freeze event is occurring, and performs an action based on the determination. In some examples, the system shuts off the treatment device, alerts an operator, reduces the cooling, and/or limits an amount of further cooling, in response to a determined treatment event. The system further applies a plurality of algorithms to detected signals in parallel to arrive at a plurality of estimates of whether a freeze event is occurring and confidences associated with the estimates. The estimates are used to evaluate whether the freeze event is in fact occurring.
