There is a mitzvah to recite the bracha of Birchas Hachama once every twenty-eight years, when the sun and moon return to the exact position in the sky in which they were placed at the time of creation. This phenomenon will occur this year, on April 8th, Erev Pesach. {Shulchan Aruch w/Mishnah Brurah 229:2, Mes. Berachos 59b}
The bracha to be recited is the same as said when one sees lightning: “Boruch Attah Hashem Elokeinu Melech Haolom, Oiseh Maaseh Bereishis.” {Shulchan Aruch w/Mishnah Brurah 229:2}
There is major disagreement amongst the poskim as to whether women are obligated, or even permitted to make this bracha. For Ashkenazim, many women rely on the p’sak of the Chazon Ish and the Maharil Diskin, who permitted women to make the bracha with the name of Hashem. For Sefardim, however, the Ben Ish Chai, and more recently Rav Ovadia Yosef, rule that women should not make the bracha on their own. Rather, they should answer Amein to the baracha made by a man.
{Birchas Hachama (citing Chazon Ish), S’U Maharil Diskin 2:KA:5:26, S’U Yechave Daas 4:18, Ben Ish Chai Parshas Eikev 19, S’U Minchas Yitzchok 8:34, S’U Chasam Sofer OC 56, S’U Ksav Sofer 34}
* From Matzav.com
UPDATE: I had the privilege of hearing a shiur about this yesterday from Harav Tzvi Sobolofsky Shlit"a. Unfortunately the article above neglects to go into the detail of the machlokes between those who say that woman should or should not recite Birchas Hachama.
I strongly recommend listening to this shiur to understand some of the Halachik implications of this uncommon occassion.
