The cataclysm in Noah’s day was probably followed by the ice age.
While glaciers covered the areas we now know as Canada and northern Europe, it is reasonable to assume that even regions now covered by sand had a much moister climate.
A recent study suggests that this indeed was the case. While the date it gives is off by 2,000 years or so, the findings as such seem to corroborate the history written in Genesis. An article in Science Daily says:
“As little as 6,000 years ago, the vast Sahara Desert was covered in grassland that received plenty of rainfall, but shifts in the world's weather patterns abruptly transformed the vegetated region into some of the driest land on Earth. A Texas A&M university researcher is trying to uncover the clues responsible for this enormous climate transformation -- and the findings could lead to better rainfall predictions worldwide.”
The researchers attempted to explain the current aridness of Sahara by invoking the Hadley circulation:
“The Hadley circulation is a tropical atmospheric circulation that rises near the equator. It is linked to the subtropical trade winds, tropical rainbelts, and affects the position of severe storms, hurricanes, and the jet stream. Where it descends in the subtropics, it can create desert-like conditions.”
They don’t seem to know why the tropical rain belt could have moved so far towards the north.
It seems that geologists and other scientists can thank – or blame – Charles Lyell for this uncertainty. Lyell, who popularised uniformitarism, sought to free geology from Moses (i.e. the biblical flood). While catastrophism has made a comeback, most researchers still detest the idea of a year-long global flood.