The last (Vashon) glaciation of the Puget Lowland 


  • global sea level
  • ice advance and retreat
  • isostatic depression and rebound
  • initial topography (a fiction!)
Ice advance and retreat were rapid. Seattle was covered by ice for less than 2,000 years. At glacial maximum about 1 km (3,000 ft) of ice covered Seattle.

fresh water
salt water

Ralph A. Haugerud -USGS