Hurricane Hilary is expected to slam into Southern California on Sunday as a rare tropical storm, unleashing floods, fierce winds and heavy downpours as residents evacuate, parks and beaches close and first responders brace for water rescues.

Hilary is now a Category 1 storm with maximum winds of 80 miles per hour as it barrels north-northwest at a speed of around 21 mph, according to the National Hurricane Center. It was about 285 miles south-southeast of San Diego as of 5 a.m. local time Sunday.

The hurricane is expected to weaken to a tropical storm before it reaches the US – but it’ll still likely pack a powerful punch in the Southwest, with “catastrophic and life-threatening” flooding expected, according to the hurricane center.

The storm is forecast to dump 3 to 6 inches of rain – or even 10 inches in some areas – and whip up damaging winds that can knock power out for many. The worst of it is expected Sunday into Monday.

California Gov. Gavin Newsom proclaimed a state of emergency Saturday for a large swath of Southern California to support hurricane response and recovery efforts, according to the governor’s office.