Based on data produced by Kaira below is a really simple heatmap visualization of migration rates to locations in every year 1912-1966 as was catalogued in Siirtokarjalaisten tie books series. When winter war broke in 1939, there was a huge migration to Finland. After winter war a similar migration is seen back to Karelia. When Continuation War began, final migration wave is seen back to Finland.

Link to fullscreen visualization