Note that two the storms you're referring to (Iselle and Julio) may have similar predicted paths, but they currently 1000 miles away from each other, and will definitely not merge. Iselle is already impacting Hawaii, while Julio will not approach for several days (assuming the current forecast verifies).
Both FTDNA and Ancestry sponsor groups or projects where people in the same haplogroup can exchange information and maybe even find an ancient connection. But Y-DNA and mtDNA are intended to check ancient bloodlines, 10,000-50,000 or so years ago. They are not generally useful by themselves for genealogy.
As of May 2008, nearly 70% of the Y-DNA results submitted to the Ybase website were Haplogroup R1b, while only 17% were Haplogroup I and 7% were Haplogroup R1a. A 2005 study found that 58% of white American men are in Haplogroup R1b.aplogroup R1b1 (M343, P25) (Western Europeans). Most of the participants in the Cheek DNA study, including everyone in the main related groupswhat we've been calling Group 1 and Group 2 (see Results Summary)are in Haplogroup R1b1. This is the most common Y-DNA haplogroup in western Europe.