In addition to kaatunut's writeup:

A brief summary of how time works in WoT:
Think of a spinning wheel/loom, spinning threads to make fabric. In the WoT universe, each thread represents a person. As people affect events, their threads change, along with other threads affected. These shapes that the threads take are known as the Pattern. In some cases, a person or group of people can affect other threads to an extreme level, drawing them into a pattern known as The Lace of Ages. People capable of causing such great changes in the Pattern are known as ta'veren.

But I digress.
In any event, balefire is capable of 'burning' a selected thread/person out of the pattern, actually destroying their existence before the destruction even occurs. Such destruction can be likened to pulling threads out of an article of clothing, eventually weakening the weave until the cloth falls apart.