Hurricane Rick is now a category five storm, churning waters off Mexico's Pacific coast at 260 kilometers per hour.
The U.S. National Hurricane Center in Miami said late Saturday that Rick's wind speeds accelerated, making the storm the highest-rated, most dangerous type of hurricane.
U.S. weather forecasters said Rick was located about 470 kilometers south of the port of Manzanillo, and was moving north at a pace of about 24 kilometers an hour.
They say Rick is an "extremely dangerous" storm and warn it could hit land (the Baja California peninsula) sometime next week.
Forecasters say even though the core of the storm will likely remain offshore for the next few days, Mexico's southern coast could still be pounded by rains Saturday night into Sunday morning.
Rick is the seventh hurricane of this year's eastern north Pacific season.