Melting of ice within the ice dam would have created a massive lake up to 2 miles deep.
When the dam finally broke in a catastrophic crash, you'd had a tsunami leaving Antarctica headed North with the power to climb thousands of feet in altitude as it hit continental masses.
Guy would have had to be hunting birds of paradise up in the Java/Sumatran mountains to survive that, and he'd still have to be on the North slopes!
Just about the only population that'd been left relatively intact would be living in Northern Asia or Central Africa.
Some think the Laurentide ice sheet floated, then broke in half and went crashing into Hudson Bay . Gigantic tsunamis!! Could explain why even the Tibeteans have flood stories of the 'mountain-topping' variety.