Disasters
Disasters are happening all over the world, and that is why some people are unhappy. The worst disaster in Korea is called "Mami". It was a typhon. I didn't see it but I heard it. My dad siad that it was worst because it was the strongest. I also read books about it. It said that Mami was strong enough to break the window. I couldn't imagine about a typhoon like that. I haven't experienced it. The worst disaster in my mind would be the flood that was over my ankle. I was too weak. My dad knows how to prepare during the situation. I guess I have to learn how to, too!! We have to learn how to face it or else, many people will die. We have to take care ourselves.

Julie: Disasters are happening all over the world. And that is why some people are unhappy. The worst disaster in Korea is Called "Mami" It was a Typhon. And I didn't saw it but hear it.
Correct: Disasters are happening all over the world, and that is why some people are unhappy. The worst disaster in Korea is called "Mami". It was a typhon. I didn't see it but I heard it.
Explanation: You usually commit the same grammar mistakes. When you use did not, the main verb should be in present tense.

Julie: My dad siad that it was a worst because it was the strongest. I also read books about it. It said that Mami was Strong enough to break the window. I couldn't imagine about a typhon like that. I haven't experienced it.
Correct:  My dad siad that it was worst because it was the strongest. I also read books about it. It said that Mami was strong enough to break the window. I couldn't imagine about a typhoon like that. I haven't experienced it.
Explanation: Be careful of your word spelling. If you are not sure about it, consult a dictionary and look for its correct spelling.

Julie: The worst disasters in my mind was the flood that was over my ankle. I was too weak. My dad know how to prepare it. I guess I have to learn how to, too!!We have to learn to face it. Or else, many people will die. We have to take care ourself not saying that the disasters did the damage.
Correct:  The worst disaster in my mind would be the flood that was over my ankle. I was too weak. My dad knows how to prepare during the situation. I guess I have to learn how to, too!! We have to learn how to face it or else, many people will die. We have to take care ourselves.
Explanation: Review the Subject-Verb agreement. Check first your subject before you write down the verb.

Hello Julie! Great work! Just be aware of your grammar mistakes so you will not commit the same mistakes again in your next composition.:)