Reading up on the #Cordilleran ice sheet, which is/was the ice sheet on the west coast of North America during the current period of #glaciation (from 2,580,000 years ago to present.)

#Wikipedia's article has an uncited section about #Refugia which includes a possibly controversial statement - needs tagging:

"…evidence of ice-free refugia above present sea level north of the Olympic Peninsula has been refuted by genetic and geological studies since the middle 1990s."

https://en.wikipedia.org/wiki/Cordilleran_ice_sheet#Refugia