Hurricane Odile strengthened to a powerful category four storm on Sunday, dumping heavy rains and triggering huge waves as it swirled off Mexico's Pacific Coast.
The narrow Baja California peninsula was hit especially hard, with mountainous areas in some western states expected to see up to 38 centimeters (15 inches) of rain from the storm, according to the US National Hurricane Center.
"These rains are likely to result in life-threatening flash floods and mudslides," the Miami-based NHC warned.
Hurricane Odile is now the second highest on the five-point Saffir-Simpson scale, which measures wind speed. This level of hurricane can potentially cause catastrophic damage.
The large storm had hurricane force winds extending outward up to 75 kilometers (47 miles) from the center, and tropical storm force winds extending outward up to 295 kilometers.
Odile's winds were blowing at 217 kilometers per hour, the US National Hurricane Center said in its 0900 GMT bulletin.
The storm was located about 315 kilometers west of Manzanillo, home to Mexico's busiest port, as it moved north-northwest at 24 kilometers per hour.
A hurricane warning was in effect for the west coast of Baja California Sur to Puerto San Andresito. A hurricane watch was in effect for other parts of the peninsula.
The NHC warned of "additional strengthening" before Odile nears the southern portion of Baja California Sur, and passes over later Sunday and Monday.
Swells likely to produce "life-threatening surf and rip current conditions" were expected along southern portions of the Baja California peninsula and the southern Gulf of California on Sunday.
In the Atlantic, meanwhile, Tropical Storm Edouard was strengthening in the open seas and was expected to become a hurricane later Sunday.