why is the storm so symbolic in the play king Lear?

The storm symbolizes madness. Shakespeare vividly portrays the transformation of man into storm and storm into man as Lear goes mad. Personifying the storm with himself and the children he has begotten, Lear wails, "Rumble thy bellyful. Spit, fire. Spout, rain./ Nor rain, wind, thunder, fire are my daughters" (III.2.14-15). The storm is given a belly and the elements are compared to daughters. Note even the sound effects are called for at key points in the dialogue to echo Lear's mutation. "Storm still " is included by Shakespeare, for example, between poor Tom's continuing rants and Lear's conclusion that his madness must be the result of the betrayal of his daughters (III.4.59-61).

In this state of rugged, stripped, essential man, Lear is able to focus on some important human issues that he has overlooked as king. Left to battle the elements of nature and the storms that are its products like the poor, Lear is forced to think on the daily lives of the homeless and his ignorance of the poor's situation. He comments, "Poor naked wretches, wheresoe'er you are,/ That bide the pelting of this pitiless storm,/ How shall your houseless heads and unfed sides,/ Your looped and windowed raggedness, defend you/ From seasons such as these? O, I have ta'en/ Too little care of this!" (III.4.28-33). This is a climactic moment for Lear, as he stands on the threshold of madness. He will descend, it seems, as soon as he comes face to face with Edgar the reflection of madness he holds as philosophy and wisdom. And perhaps Lear comes much closer to a wisdom of humankind as a result. Madly, he attempts to strip himself naked only moments later before being stopped by the Fool, whose madness (when faced with Lear's) becomes simple complacency as he tries to look out for his master's safekeeping. In this, we see again how sane the Fool has been all along and how real Lear's madness is to make the Fool's speech become so practical. Lear is trying to physically strip himself of the artifice he has noticed within himself and most of mankind. He wishes to be put on par with poor Tom, a man who has lived much closer, he thinks, to the truth of nature.