Rainbows are the sign of God's covenant with Noah. Before the Deluge, [ante-deluvian] there were no rainbows, because the atmosphere did not have significant quantities of water in it, nor did it ever rain. The whole earth was watered from a spring welling up from the ground. It was probably a fairly even world with no or very few mountains and hills, and a high water table. Since much of today's water was in an underground sea, the world was primarily unflooded except for some oceans and big lovely lakes. Since the flood, the new water cycle has formed and washed a lot of the salt and nutrients into the sea. Now we see deserts, uneven distribution of nutrients, dry and swampy regions, and a very saline sea.
There probably were no deserts, no mountains, no rain nor clouds, and the earth's ozone layer and ionosphere were probably different. The planet may have been pleasantly warm all around from more even geoconvection and less humid skies, so there would be low winds most everywhere and few storms, hurricanes, blizzards, and probably even the chilliest parts of the earth were probably around freezing or so from low wind and ample plant life and uniform convection and watering, and if they did get very cold or hot it was at low humidity.
The artic regions are currently so frosty mostly because of supercharged permanent high pressure zones from geoconvection causing upper-atmosphere [very cold] winds to barrel down at the exact [~50 miles] north and south poles at around 200mph, bringing wind chill and coldness from the void of space right into earth's atmosphere. Geoconvection is when the sun's longwave rays beat down on earth, pass through clouds and most water, and turn into heat [shortwaves] when they pass through solid material. This is why the inside of your car gets unevenly hot in the sun when the windows are rolled up. The sun's energy turns into heat on the car's body and interior and gets trapped in the car's interior. Hot air expands, northward and southward from the equatorial region where most of the sun hits. If you opened the car doors heat would billow out. So it billows on earth, trapped by gravity, and other particles trapped by the ionosphere. This heat expands basically to the poles, where it all crunches up and has to go back down instead of out to space. So the super high pressure at the poles, and the cold upper atmosphere wind.
I speculate that if the earth had ~99% land cover with sporadic and small lakes, the low pressure zones over oceans would not exist, high geoconvection from equatorial regions would be matched by a larger arctic pressure force from arctic and polar landmass convection. The resulting pressure imbalance and rush north and south would be slower, we would have lower pressure levels at the poles, and the dry air would not contain freezing water or conduct so much coldness to the poles, and down to the top and bottom 33* of earth.
I know much geology, but I do not have major skills/funk when it comes to internal earth effects. So my hypotheses of the endogeo [underground] effects of the deluge are less solid and may contain gross inequities. However, I still wonder, and learn by hypothesis. You may learn too.
I wonder if the flood changed earth's axis rotation. I read that the Indonesian earthquake in December 2004 changed the earth's rotation slightly. That was from a single event. If a large portion of the deluvian water came from the Alaskan [now] deep sea trenches, that would be enough to cause the earth the tilt substantially on its axis, and could be stabilized later by waves, or crashing against mountains, or water crashing against itself at the south pole/ in the south pacific. This could also have set off a series of earthquakes and volcanos from the cracking and partial destruction of earth's crust, causing minor mountains and ranges and establish the current crust imbalance. That quantity of water could easily have crushed continents and caused the plates to crack and reform.
Due to creation, I don't think there were seperate tectonic plates before the great flood, or if there were they were not substantial. There does seem to be a Pangaea shape in the continental forms. The Pangaea plate may have been the entire earth's surface, torn apart by the flood. Our landforms may simply be the highest ground among those collected plates, and the spaces in between, where land was burst apart and probably plain magma showed, which was instantly solidified by the new oceans.
You'd see the flood from space.
If the occurance of the flood changed the earth's axis, it also created or exacerbated the effects of the seasons. If the deluge happened about 6000 years ago[?] and we see the earth today, ~300-330 generations later, could those environments produced be great enough to cause the phenotype changes [down-evolution] seen in human populations? It could be. Consider the dramatic change in environment that was likely experienced by contemporary humans. [80% of England's contemporary population is descended from Henry VIII, some 350 [?] years ago. I bet ~100% descended from Noah's family, and another 100% from Adam and Eve.]
White colored caucasian skin is more resistant to frostbite. People who went to the northern climates probably turned white like this in 50 generations or less, or died. Their skin also allows in more sunlight for the body to turn into Vitamin D. Yes, you make Vitamin D from your skin, and you need it. Above 40* latitude, the amount of sun people experience is usually not enough to give the body all the vitamin D they need. Hence cow's milk for extra vitamin D, hence cheese, hence ~90% of white folk are not lactose intolerant, and something like 50% of black folk and Pacific Islanders are lactose intolerant. This is internal down-evolution.
Black folk where the sun beats down without substantial vegetation coverage after the flood, and with a large amount of prisming atmospheric water, got black skin to shield them from the sun. A black person can stay in the sun for much longer, sometimes up to 90 minutes or more, without getting a sunburn. White folk can burn in like 10 minutes. This is down-evolution. Incas and people living in high altitudes develop barrel-chests to hold more oxygen. Their blood may also have more hemoglobin to make up for the reduced oxygen content. Could these have expressed in ~300 generations? I believe so. The original person [Adam] was probably olive colored and entirely genetically unspecialized. Putty colored, you say? Look at us today. If you're human, you have genetic expression. Whiteness, blackness, special nutritional requirements due to historical environment, that is expression.
You may also consider that all dogs evolved from wild wolf-like creatures during the period of domestication, which according to creation is certainly less than 8000 years. Humans can do it too.