Answer:

. . . on that day all the fountains of the great deep were broken up, and the windows of heaven were opened (GENESIS 7:11).

JOB 37:9–10

The Bible is a book of history and altogether true, but God does not reveal everything to us in this book. However, if we look at what we know about the worldwide flood from the Bible, then look at the evidence of glaciers and ice sheets that once covered at least one-third of the earth, we see that the Bible does give us some clues about the Ice Age. A catastrophe as huge as Noah’s flood drastically changed the climate on the earth, creating conditions perfect for an Ice Age at the end of the Flood. 

The Bible tells us that the fountains of the great deep burst forth. This was unlike anything that we can even imagine! This breaking up of the earth caused the oceans to heat up and caused ash and dust to fill the air, blocking out sunlight, making the temperatures on earth cooler. As the warm water from the oceans evaporated into the air, forming clouds, the colder air over the earth caused wintry conditions, lots of snow, and ice glaciers. This could have very easily caused an Ice Age that lasted hundreds of years. When we start with what the Bible tells us, we can find the truth! 

Look at our verse in Job. Maybe this is a reference to the Ice Age at the time of Job.

Source: https://answersingenesis.org/kids/ice-age/why-doesnt-the-bible-tell-us-about-the-ice-age/