Man was created with only a very limited capacity to appreciate the awesome power, incredible vastness and sublime beauty of God’s Creation.  However, God, in His wisdom, placed within His world, certain natural phenomena which capture our attention and help us better appreciate His handiwork and our place in it.  Our Rabbis, ever so cognizant of man and his role in Creation, established various brachot or blessings, to help man acknowledge and appreciate these lofty ideas.
    The Anshei Kenesset HaGedolah, the rabbinic body that prophetically composed the brachot that we make today, established brachot on five types of physical phenomena: shooting stars or meteorites, earthquakes, thunder, lightning and unusually strong winds. They also established brachot for when we are struck by the sublime beauty that we encounter when we view the earth’s great oceans, mountains, deserts, etc.
    The Gemara explains that there are two brachot that the Anshei Kenesset HaGedolah established; she’ cocho u’gevurato ma’leh olam that translates as, “that His strength and His might fill the world,” and oseh ma’aseh bereishit which translates as, “He makes the act of creation.” The fact that the bracha of she’cocho u’gevurato ma’leh olam ends with the words “fill the world,” shows us that it was established for physical phenomena that many people can see or experience at once. Therefore, on the physical phenomena one has a choice to make either of the two brachot. However, on geographical phenomena, which are only seen by the people in close proximity, only the bracha of oseh ma’aseh bereishit is made.
    The Mishnah Berurah explains that even though a person has a choice of which bracha to make, the custom has become to say oseh ma’aseh bereishit on lightning and she’cocho u’gevurato ma’leh olam on thunder. Therefore, if one sees lightning before hearing the thunder, two separate brachot are made. The more common scenario is to hear the thunder from a distance and then when the storm comes closer to see the lightning. In such a case two brachot are also made. However, if they came at once, only one bracha is made and the preferred one to make in this situation is oseh ma’aseh bereishit.
    These brachot may only be made immediately after experiencing these phenomena. One may not interrupt by speaking or engaging in any other activities.   The entire time that the clouds have not dissipated from the storm, one set of brachot suffices. If the clouds dissipate, the sky clears and then another, separate storm roles in, new brachot are made. However, if a strong wind blows and the clouds just scatter, new brachot are not made.
    In 1948, when the sound of bomb blasts was all too common in Israel, the Slabodka Rosh Yeshiva, Rabbi Yitzchak Isaac Sher, took aside a ten-year-old boy and asked him, in a good-humored way, what blessing should be made on the sound of a bomb blast. When the boy could not answer, Rabbi Sher told him, the same as thunder; she’cocho u’gevurato ma’leh olam. Rabbi Sher was not giving the boy a practical halachic ruling; rather, he was telling him that bomb blasts are no different than unexpected thunder on a cloudless day. They are both a reminder of Hashem’s power.
    Thunder, the Talmud tells us, exists only to straighten the crookedness of our hearts, to strip away the layers of our self-deception. Rabbi Sher explained that every explosion in the holy city of Jerusalem, was like a clap of thunder reminding us of His power and awesome might.  So too, all of the other phenomena upon which we say these special brachot, they all serve to remind us of and, hopefully, bring us closer to HaKodesh Baruchu.