If there are sheets of several-kilometer (mile) thick ice sitting on you, you might think it's a little heavy. Well, the land thinks so as well. During the last glacial period, great sheets of ice covered much of North America. The sheer weight of the ice depressed the land and today it is still bouncing back in many areas.

Another relic of the last Ice Age to visit is the (remote) Bering Land Bridge National Preserve - it preserves a remnant of an ancient land bridge that once connected North America with Asia.

The Post-Glacial Rebound And Future

Post-glacial rebound is also called isostatic rebound and is the rise of land masses after the crushing weight of ice sheets has disappeared. The raising effects of the post-glacial rebound are obvious in parts of Northern Eurasia, Patagonia, Antarctica, and North America.

  • Laurentide Ice Sheet: Name of The North American Icesheet That Was Centered Over Hudson Bay

The sheets of ice that once covered much of the Northern Hemisphere was as much as 3 kilometers thick at the glacial maximum of around 20,000 years ago. The weight of this ice caused the Earth's crust to deform and warp downward (and it forced the viscoelastic mantle material to flow away). With the uplift the mantle material returns. It will take many thousands of years more before an equilibrium is reached.

*' Future: The Rebound Will Continue For Thousands of Years More (At Least 10,000 years)

At first, there was the elastic response that was much quicker. Today the slower rebound averages around 1 cm (or a third of an inch) a year.

Related: 13 Alarming Images Of Glaciers Melting (12 People Who Don’t Care)

Northern Canada And The Hudson Bay

Nowhere is as extreme as in much of northern Canada. Today the land in central and northern Ontario (and surrounding provinces) is rising. The land of northern Ontario around the shores of Hudson Bay and James Bay is rising particularly quickly.

The fastest rate in Ontario is around 1 to 1.3 meters (or 3.4 to 4.3 feet) per hundred years. The first settlement in Canada was established in 1604 - around 400 years ago. That would mean that these lands are now 4 to 5.2 meters or 13.6 to 17.2 feet higher now than then. The upper end is approaching the height of an average 2 story house.

  • Fastest Rate: In Parts Land Is Rebounding At Between 1-1.3 Meters or 3.4-4.3 Feet Per Year
  • Fastest Location: The Land Between Fort Severn, Peawanuck, and Cape Henrietta Maria is Rising The Fastest In Ontario

Much of the rest of northern Canada is also rising, although less dramatically (although the lower prairie provinces and Maritime provinces seem to be sinking).

As the ice started to melt, the land started to rise around 15,000 years ago. 8,000 years ago, Cape Henrietta Maria (in Ontario where James Bay and Hudson Bay merge) was over 100 meters (300 feet) below the sea. That ancient sea was called Tyrrell Sea - that land emerged around 7,000 years ago.

  • Began: The Rebound Began Around 15,000 Years Ago

Today one can find a series of abandoned beaches around Hudson Bay. Its oldest and highest beaches farthest inland developed around 7,500 years ago. At that time the bay's relative sea level was around 130 meters or 430 feet higher than today. One can trace these old beaches all the way down to the present sea level and the present beaches.

  • Future: Hudson Bay Is Likely To Continue To Strink As New Land Rises Up

But the process hasn't stopped and in the future beaches will form along Hudson Bay which is today covered in tidal flats. While there in the Hudson Bay, go on a polar expedition!

Related: The Troll's Tongue Is One Of The Most Famous Landmarks In Norway

Glacial Rebound In Europe

Over in the Nordic countries of Europe, one can observe the effects of post-glacial rebound in much more populated areas. Much of Finland only owes its existence due to the rebound as much of it was previously depressed under the sea.

  • Finland: Much Of Finland Was Once Depressed Below Sea Level
  • Growing Finland: Finland's Today Area is Growing By about 7 sq Kilometers Annually

The process is continuing. The Gulf of Bothnia is the large body of water separating Finland from Sweden and the land under this shallow sea is also rebounding. It is thought that in around another 2,000 years the gulf will eventually close up at Kvarken.

  • Gulf of Bothnia: Separates Finland and Sweden, Is Likely To Close Up In Around 2,000 Years
  • Kvarken: UNESCO Listed "Type Area" To Illustrate The Effect of Post-Glacial Rebound

In other places in the Nordic countries, ports (like Tornio and Pori) have had to move their harbors several times as they become unusable from the rebound.

  • Placenames: Some Placenames In Nordic Countries Show That They Were Once Islands or Something Else

Some placenames in the region reflect the changes that have occurred from the rebound. Today there are inland places called 'island', 'skerry', 'rock', 'point' and 'sound'. An example is Oulunsalo in northern Finland means "island of Oulujoki but is today a peninsula.

Next: The Best Time To Visit Iceland And Why Everyone Wants To Visit This Mesmerizing Island