Ice Age definition:
A cold period marked by episodes of extensive glaciations alternating with episodes of relative warmth. Any geologic period during which thick ice sheets cover vast areas of land. Such periods of large-scale glaciations may last several million years and drastically reshape surface features of entire continents. A number of major ice ages have occurred throughout the Earth's history; the most recent periods were during the Pleistocene Epoch.
There have been at least four major ice ages in the Earth's past. The earliest hypothesized ice age is believed to have occurred around 2.7 to 2.3 billion years ago during the early Proterozoic Eon. The earliest well-documented ice age, and probably the most severe of the last 1 billion years, occurred from 800 to 600 million years ago (the Cryogenian period) and may have produced a Snowball Earth in which permanent sea ice extended to or very near the equator. It has been suggested that the end of this ice age was responsible for the subsequent Cambrian Explosion, though this theory is recent and controversial. A minor ice age occurred from 460 to 430 million years ago, during the Late Ordovician Period. There were extensive polar ice caps at intervals from 350 to 260 million years ago, during the Carboniferous and early Permian Periods, associated with the Karoo Ice Age. Sediment records showing the fluctuating sequences of glacials and interglacials during the last several million years.The present ice age began 40 million years ago with the growth of an ice sheet in Antarctica. It intensified during the Pleistocene (starting around 3 million years ago) with the spread of ice sheets in the Northern Hemisphere. Since then, the world has seen cycles of glaciation with ice sheets advancing and retreating on 40,000- and 100,000-year time scales. The last glacial period ended about ten thousand years ago.

Iceberg is a large mass of glacial ice broken off and drifted from parent glaciers or ice shelves along polar seas. Icebergs should be distinguished from polar pack ice, which is sea ice, or frozen seawater, though rafted or hum mocked fragments of the latter may resemble small bergs. Icebergs are classified by shape and size. The terms used are arched, blocky, dome, pinnacled, tabular, valley, and weathered for berg description, and bergy-bit and growler for berg fragments ranging smaller than cottage size above water. The lifespan of an iceberg may be indefinite while the berg remains in cold polar waters, eroding only slightly during summer months. But under the influence of ocean currents, an iceberg that drifts into warmer water will disintegrate rapidly.

Premonition:
The word Premonition refers to a situation when future events are foreknown or forecast. Premonitions are attributed to the presence of supernatural or paranormal abilities. A paranormal impression warning of a future event. Premonitions may range from vague feelings of disquiet, suggestive of impending disaster, to actual hallucinations, visual or auditory. Dreams are frequent vehicles of premonitions, either direct or symbolical, as well as veridical dreams. Spiritualists do not know if the warning comes from an external intelligent source such as a knowledgeable spirit being, from claivoyance (precognition), the intuitive projection of the outcome of presently existing trends, or coincidence or self-fulfilling prophecy, a form of autosuggestion. A premonition differs from prediction. Reportedly the latter has a degree of precision and tends to detail the basic who, what, when, where, and how questions. When the event foreseen is not precisely outlined or is too insubstantial to prompt a prophetic utterance, "premonition" is the more appropriate term. For vague future events of a personal nature, "presentiment" is employed. Many prominent people have left records illustrative of the general nature of premonitions: Charles Dickens dreamed of a lady in a red shawl, who said: "I am Miss Napier." He did not know who this woman was. Some hours later, he was visited by two ladies, and a girl in a red shawl was introduced as Miss Napier. (Proceedings of the American Society for Psychical Research, vol. 14, 1920).
Sir Oliver Lodge quoted the account of an English minister who dreamed of a terrible storm and lightning that entered the dining room and destroyed the chimneys of the roof opposite. Under the impression of the dream, although it was bright sunshine, he directed his wife to prepare lunch at an early hour. Events happened just as in the dream. Soon a storm broke out, and lightening struck through the dining room and demolished the chimneys of the neighboring roof.
President Abraham Lincoln had strange presentiments of his coming end. John Forster, in his Life of Dickens (3 vols., 1872), quoted a letter written to him by Dickens, dated February 4, 1868. Charles Summer had told Dickens that on the day of Lincoln's assassination an extraordinary change was noticeable in him. Lincoln said: "Gentlemen, something extraordinary will happen, and that very soon." Later he spoke of a dream that came to him for the third time and said: "I am on a deep, broad, rolling river; I am in a boat, and I am falling in! I am falling in!" Six weeks before his assassination he saw a great concourse of mourners in the White House in a dream. The mourners surrounded a coffin in which he saw his own body. Presidents Garfield and McKinley also had premonitions of their violent ends.