Solid line is the approximate extent of glaciation in the last Ice Age, 11,000 years ago. All ice above it. People below it could survive. Dotted line is the approximate extent in the previous Ice Age.
“Climbing ever higher on the bodies of their fallen comrades, they tried to stay above the ever deepening snow. Still it kept coming. Four stories deep. Six stories deep. Nine. All in one day. Still they kept climbing, nine stories into the sky.”—Not By Fire, But By Ice
Via Ice-Age Now