Genesis 2:5-6 indeed indicates that at one stage of the Earth's creation it did not rain, but instead it was watered from underground springs:
Genesis 2:5 - "No shrub had yet appeared on the earth and no plant had yet sprung up, for the LORD God had not sent rain on the earth and there was no one to work the ground, (6) but streams came up from the earth and watered the whole surface of the ground."
This verse alone is not evidence that there was still no rain in Noah’s time because the said verse refers to a time before the creation of Adam, but there is more biblical evidence to show that there was still no rain right up until the flood:
Genesis 9:13 - "Now I have set my rainbow in the clouds and it will be the sign of the covenant between me and the earth. (14) Whenever I bring clouds over the earth and the rainbow appears in the clouds (15) I will remember my covenant between me and you and all living creatures of every kind.”
Of course rainbows are caused by clouds passing over the earth as the verse states, which means that before the flood there were no rainbows - because there was no rain or clouds in the sky before the flood!
The Bible definitely refers to an expanse of water above the firmament during the time that it did not rain from creation until the flood:
Genesis 1:7 – “And God made the firmament and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.”
2 Peter 3:5 – “They deliberately forget that God made the heavens by the word of his command, and he brought the earth out from the water and surrounded it with water.”
(In most translation it says that the earth stood ‘both out of the water and in the water’).
We are also told that Noah believed in things God told about that had never been seen before:
Hebrews 11:7 – “By faith Noah, when warned about things not yet seen, in holy fear built an ark to save his family.”
Rain and floods had never been seen in Noah’s time so it was a significant faith factor for him to believe God about such things as the flood.
Whatever form this water above the expanse was in during Noah's time, it was not in the form of regular clouds. However it must have been an immense amount of water:
Genesis 7:11 – “In the six hundredth year of Noah's life, on the seventeenth day of the second month--on that day all the springs of the great deep burst forth, and the floodgates of the heavens were opened.” (NIV)
(Windows of the heavens were opened).(KJV)
Many Bibles translate it as ‘windows of the heavens’ – with a window being like something transparent that is holding something out or in (usually air, but in this case water).
It did not rain, but there was still enough water up there to create a one off torrent of rain that fell consistently for over a month, day and night without stopping during the flood.
This water above the firmament could well have been in the form of ice crystals suspended in space just outside of the earth's atmosphere and held in place by the Earth's gravity - as is a moon or a planets rings held in place by gravity. This is very possible because Saturn’s rings are known to be composed mainly of ice.
This translucent layer water around the earth would not only have filtered out immense amounts of radiation coming from space but would have also prevented heat from escaping the atmosphere, making the climate much more moderate and consistently warmer. It also compressed the atmosphere beneath it allowing for much higher concentration of oxygen to be present at ground level.
(Discover, February, 1988, p. 12.) -
“Another interesting feature of the early earth atmosphere was enhanced oxygen. The analysis of microscopic air bubbles trapped in fossilized tree resin gave Robert Berner of Yale and Gary Landis of the U.S. Geological Survey a glimpse into the ancient past… These breaths (produced by a quadruple mass spectrometer) disclosed some surprising evidence: the ancient air contained 50 percent more oxygen than the air today. Landis believes that the reduction in oxygen could have led to the dinosaur’s demise.”
In the past animals, people and plants could grow to be massive sizes and could live up to ten times longer than what is possible today, this is proved by the dinosaurs which cannot live today because there is not enough oxygen at ground level to fuel such a massive body. We see this trend in the Genealogies of Adam as recorded in Genesis chapter 5. The people of this time were living to be over 900 years old! Genesis 6:4 also tells us that - there were giants on the earth in those days.