The family of Rabbi Reuven Bauman will tear kriah and sit shiva today, according to a Psak the family received.
The family was told by their Rav that if the body is still not found by today at 12:40 PM, which is the time Rabbi Bauman disappeared, they should rip kriah and sit shiva.

The Coast Guards called off their search for Rabbi Reuven Bauman at about 11:30 a.m. Wednesday, after having searched about 347 square nautical miles, which translates to about 459 square miles.
Volunteers from Hatzolah and other organizations are continuing the search in hopes of recovering a body and allowing Rabbi Bauman to have a proper kevura.
Rabbi Bauman was pulled into the surf after jumping into the water to rescue a teenage boy who was caught in the riptide. He was able to rescue the boy, who was taken to the hospital and is recovering, but then was pulled into the water himself.
{Matzav.com}