On the night Hurricane Otis barreled into Acapulco, Mexico, Saúl Parra Morales received a video that only hours before would have seemed unbelievable.

For days, forecasters had predicted little more than a tropical storm. But Mr. Parra Morales watched in horror as his brother filmed the deafening gusts of wind and waves cracking against the deck of the Litos, the yacht where he worked and that proved no match for what became the most powerful storm to hit Mexico’s Pacific Coast.

“This is getting more intense,” Mr. Parra Morales’s brother, Fernando Esteban Parra Morales, said in the video. “We are nervous, but we are safe.”

He wasn’t. Fernando, a machinist, is one of the many mariners on the front lines of this tourist destination who have been missing since the Category 5 hurricane brought destruction to Acapulco last month, shocking forecasters and government officials alike.

While the Mexican authorities have not released details of the 49 people killed and 26 others left missing by the storm, relatives, business leaders and the Mexican Navy say many were captains, sailors and other boat workers caught in the hurricane’s devastating path. Some say the number of missing may be far higher.