If you look at the damage done to the middle pyramid in Giza, Malta’s caves and similar structures, the water serge seems to rise as high as 80 meters. I don’t know for sure, that it wont be higher, so the best advice I can give, is to build a floating bunker, one that can be fully submerged, and has a physical anchor and is fas flush to the landscape as possible. So when the surge hits, the water flows overhead if it surpasses 80 meters, or if its in a lower lying area. So if the area remains submerged, a salt bolt dissolves releasing the floating bunker or the manual release is activated. As the patterns in North Africa, suggest the surge was pretty intense and the waters could have remained hight for days before subsiding. So having the ability to grow your own crops in the bunker would be helpful along with seeds. The problem is paleo climatology and archeological records suggest, that the sea level was around 60 foot lower during the younger dryas, if we assume the common geological theories relating to tectonic plate movements. I only recently learned about the “Great Unconformity” mystery in the Grand Canyon. Which matches what I learned about how the crust and land masses move, not as a single giant block sliding deep under ground to the mantal in a subduction zone. Instead the crust splits, like how you shuffle cards, in a split shuffle. Where the land masses pass under one another plate, but dependant upon the contours of the land mass, passing underneath the top place, this changes the pitch of the above plate. With @Graham__Hancock theory regarding the island that disappeared in the Bahamas, that looks like it moved up to Novascocia, see pictures 2 and 3, with part of the island being where Bimany is today, where some underwater structures are found. With the elevation change, being less about sea level rises and pitch changes, that explain why doggerland in the South east of England was submerged by sea level rises. Is exactly at the point where the South East of England in Kent, Sussex and Essex, are lowering, at the same time, Scotland is gaining land as the coastline rises from the ocean. Right now, there are several holes I want to answer including where the axis would move to next. As I feel ground water deposits would play a part, and where as the Axis position should go to the Himalayas, its very possible due to the 3 gorges dam, that the Axis could move closer to the area in China. Or move to a unexpected point of equilibrium. If your prepping, and can alter the concentrations of Carbon dioxide, exposure to the plants, lower the concentration to between 260ppm and 300ppm, as the crops produced would be high in nutrients, as counter intuitive as it sounds, the more Carbon Dioxide, the plants and trees ability to absorb nutrients decreases. So for long term storage, using high nutrient dense raw materials will sustain for longer whilst needing to consume less!