The hurricane, downgraded from Category 5 earlier in the day, reached land near Acapulco and is moving into Southern Mexico, bringing heavy rainfall and flash flooding with hurricane-force winds, the latest NHC advisory said.

The storm could bring up to 20 inches (51 cm) of rain in parts of Guerrero and Oaxaca states, with the possibility of flash floods and mudslides, a “potentially catastrophic” storm surge, and “life-threatening” surf and rip current conditions, authorities said.

Mexico’s national water agency CONAGUA warned of six-to-eight-meter surf off Guerrero – home to Acapulco – and parts of Oaxaca.

Otis is about 25 miles North-Northwest of Acapulco and blowing maximum sustained winds of 130 mph (215 kph), the Miami-based NHC added.

In Guerrero, authorities were preparing storm shelters, and the national guard said it was helping to prepare for rescues and evacuations.

Mexico’s National Civil Protection Coordination (CNPC) said power outages are being reported throughout Guerrero due to the hurricane.

The defense ministry enacted a disaster plan ahead of the storm’s arrival, President Andres Manuel Lopez Obrador said on social media late on Tuesday, as soldiers patrolled Acapulco’s emptying beaches.

Schools across Guerrero canceled classes for Wednesday ahead of Otis’ arrival, Governor Evelyn Salgado said on social media.

By Javier Verdin

(Reporting by Javier Verdin in Acapulco and Brendan O’Boyle in Mexico City; Writing by Brendan O’Boyle and Natalia Siniawski; Editing by Robert Birsel, Bernadette Baum and Jan Harvey)