Exodus

 I saw a program on how a lake in Africa turned orange due to a volcano blowing carbon dioxide into a body of water that doesn't circulate enough to disperse the CO2. It killed the livestock.

I have studied textbooks on the Bible enough to understand that God can sometimes use natural phenomena to accomplish a miracle. The manna in the wilderness, for example, was theorized to be excretion from a certain type of insect.

Regardless of whether the Nile turning red was due to a volcano or something else, the timing is miraculous, and it figures in to the part about Egyptian sorcerers being able to mimic the event.

Moses being able to capitalize on such a weird natural phenomenon that even modern Africans couldn't figure out, that's miraculous. Moses wasn't a scientist, but the phenomenon helped the people of Israel to escape from slavery.

I've frequently found that God seems to work through natural events. He created the laws of physics and such, so taking advantage of what He made is probably convenient for Him, although it makes it hard to scientifically prove His existence. Still, you can't disprove His existence, so take it as you can take it.