The reason is that a continental glacier completely disrupts the preglacial drainage system.
From the en.wikipedia.org
Ice-free corridor running north and south through Alberta and the continental glacier called Laurentide ice sheet.
From the en.wikipedia.org
Landlocked within the continent, the state is a long distance from the seas that once covered it, and the continental glacier has receded entirely from North America.
From the en.wikipedia.org
This was the first glacier in the continental United States discovered and named.
From the en.wikipedia.org
A good first stop for a glacier jaunt is the Norwegian Glacier Museum, on the southern edge of continental Europe's largest glacier, the Jostedalsbreen.
From the online.wsj.com
However, it long has been a favorite for users hiking to the Carbon Glacier, the lowest glacier in the continental United States.
From the thenewstribune.com
The road provides access to several popular hikes including the Carbon Glacier Trail, a walk to the snout of the lowest glacier in the continental United States.
From the thenewstribune.com
By the time the glacier makes its way to the extreme continental east, it will have become fully assimilated into the mainstream.
From the buffalonews.com
Instead the recent increases in glacier outflow are believed to be due to an inflow of warm water from the deep ocean, just off the continental shelf.