DS211: Rainbows exist when sunlight is reflectef in water sparks. Way before the flood there must have been rainbows as it rained before even the creation of man. The bible speaks of a humid climate.
The flood account doesnt contradict a local flood. The term whole earth is often used in the bible to describe some local things like the roman worldpower.
Flavius Josephus writes in his work 'Jewish antiquities' in paragraph 94-95 and 109 that many people fled to the high mountains and survived the flood (the wt society often quotes from that work). When you view it that all evil people living close to Noah died (but a lot that survived in other parts of the land) then not even this is a contradiction.