“A ground sea was heard; the thunder of its progress, as the waters rolled and swelled beneath me, became every moment more ominous and terrific” (198).
A ground sea is a sea with large rolling waves with no evident origin. Here it takes place under the thick layers of ice that Victor is traveling on, causing damage similar to an earthquake or tsunami. The ground sea ruins Victor’s chances of pursuing his creature into the vast wastelands of the Arctic.
Works Cited: http://www.english.upenn.edu/Projects/knarf/V3notes/ground2.html