Why don't young-earth creationists just explain things (usually considered as miracles) as miracles? I've observed some young-earth creationists attempt to link the worldwide flood of Noah's day with melting icebergs. While not critical of the science behind such an explanation, I would really like to know why young-earth creationists, in addition to a strictly literal approach, don't also leave any room for miracles in their explanations of things that are commonly regarded as miracles. Why don't they say at least "I don't know" instead of creating the faulty science?
It is always better to admit you don't know than to make something up, especially when it comes to speaking about God!
The idea that God fills in the gaps of our knowledge with his miracle super powers is called the 'God of the Gaps.' It has the problem of making God look like he decreases while our knowledge increases. It also does not adequately account for the doctrine of providence: Christians believe that all that happens is due to the hand of God. Things that happen because of the regular scientific laws are not somehow independent of God while miracles show how God acts; no instead everything is directly the act of God. But because God is an orderly being, he chooses to act in such a predictable way that we can categorise his acts into the laws of nature. The miracles are the irregular times when he decides to act outside his normal patterns, but they are ultimately no different from his other acts.
The YEC movement arose after evolution and scientific naturalism became the dominant scientific paradigm. The movement does not disagree with any data gathered by scientists, or with any real scientific laws/theories/models. Their disagreement with mainstream science is how to extrapolate from the data we have gathered in the present into the distant past. So they'll say that both sides have data X and theory Y, but their assumptions A &amp; B differ, which is why mainstream science says some rock is 3 billion years old and the YEC scientists say it is only a few thousand years old. So even though they have no direct theological relevance, the YEC movement spends a lot of time developing models they believe are scientifically plausible for the cosmology they believe in. This doesn't mean they never say that miracles have happened, just that when the Bible doesn't explicitly say one did happen, and when they can come up with a model that doesn't need a miracle, they'll usually go with such a model.