The extent of North American (Laurentide) glaciation from 18,000 years ago (18 kya) to 8 kya.


Glaciers and Climate

     Glaciers are not here in Pennsylvania today, but they were! And only about 15,000 years ago.  They covered vast areas of North America, Europe, and Asia.
     They are still  present in Alaska (covering 3% of the land there), WA (800 glaciers), MT, CA, OR, CO, and WY.
     They don't occur just in polar areas:  Mexico has 3 (above 5000 m elevation); Mt. Kilimanjaro is on the equator (above 4400 m);  obviously, areas at elevation can have glaciers.  Generally speaking, the temperature declines 3-5 degrees C for every 1000 ft gain in elevation.
     There are plenty of reminders (evidences) of glaciation:
  • Matterhorn (a horn) 
  • Cape Cod (a terminal moraine)
  • the Great Lakes
  • Long Island (a moraine)
  • NY's Finger Lakes
  • bogs and fjords
  • the fertility of our Great Plains (thanks, Canada for the outwash)
  • the grandeur of some of our most spectacular National Parks, e.g., Yellowstone.