Hurricane Hilary is expected to enter the Baja California region on Saturday evening as a powerful hurricane before reaching southern California as a rare tropical storm on Sunday amid warnings of deadly flooding. The National Hurricane Center warned of “catastrophic and life-threatening flooding” from the storm through Monday, in its most recent forecast on Saturday morning, and told residents to expect heavy rain ahead of the center of the storm. “Preparations for the impacts of flooding from rainfall should be completed as soon as possible, as heavy rain will increase ahead of the center today,” the forecast said. “In the south-western United States, flash, urban and arroyo flooding is expected, with dangerous and locally catastrophic impacts likely from tonight into Monday.” After reaching category 4 hurricane strength on Friday night, Hurricane Hilary was downgraded on Saturday to a category 3 storm with winds of up to 115mph. Mid-day on Saturday, the storm was centered approximately 350 miles (563km) south-south-west of Punta Eugenia, a western spur along the Baja California peninsula. Though the storm is expected to weaken today, it will likely stay a hurricane when it hits the coast of the Baja California peninsula. When it reaches southern California, it is forecasted to weaken to a tropical storm, the first to hit the region in 84 years. National Weather Service Los Angeles warned residents to expect rain. Rain is also expected in Nevada and Arizona, hitting areas that had experienced a record-breaking heatwave this summer. Some schools in Cabo San Lucas, Mexico, were being prepared as temporary shelters, and in La Paz, the picturesque capital of Baja California Sur state on the Sea of Cortez, police patrolled closed beaches to keep swimmers out of the whipped-up surf. Schools were shut down in five municipalities. Many homes in the border city of Tijuana, which has a population of 1.9 million, cling precariously to steep hillsides. Mayor Montserrat Caballero Ramírez said the city was setting up four shelters in high-risk zones and warning people in risky zones. “We are a vulnerable city being on one of the most visited borders in the world and because of our landscape,” she said. Meanwhile, officials in southern California are scrambling to get unhoused people off the streets and into shelters in preparation for the storm. The Los Angeles Homeless Service Authority said that 50 people have been moved from the Santa Fe Dam area to safer locations. The government agency says that more than 100 outreach teams will be activated throughout LA county through Monday. “I don’t think any of us – I know me particularly – never thought I’d be standing here talking about a hurricane or a tropical storm,” said Janice Hahn, chair of the Los Angeles county board of supervisors. The National Park Service closed Joshua Tree national park and Mojave national preserve to keep people from becoming stranded amid flooding. Cities across the region, including in Arizona, were offering sandbags to safeguard properties against floodwaters. Major League Baseball rescheduled three Sunday games in southern California, moving them to Saturday as part of split-doubleheaders. President Joe Biden said the Federal Emergency Management Agency had pre-positioned staff and supplies in the region. “I urge everyone, everyone in the path of this storm, to take precautions and listen to the guidance of state and local officials,” Biden told reporters on Friday at Camp David, where he is meeting with the leaders of Japan and South Korea. Officials in southern California were re-enforcing sand berms, built to protect low-lying coastal communities against winter surf, like in Huntington Beach, which dubs itself “Surf City USA”. In nearby Newport Beach, Tanner Atkinson waited in a line of vehicles for free sandbags at a city distribution point. “I mean a lot of people here are excited because the waves are gonna get pretty heavy,” Atkinson said. “But I mean, it’s gonna be some rain, so usually there’s some flooding and the landslides and things like that.” Hurricane officials said the storm could bring heavy rainfall to the south-western United States, dumping 3 to 6in (8 to 15cm) in places, with isolated amounts of up to 10in (25cm), in portions of southern California and southern Nevada. “Two to three inches of rainfall in southern California is unheard of” for this time of year, said Kristen Corbosiero, a University of Albany atmospheric scientist who specializes in Pacific hurricanes. “That’s a that’s a whole summer and fall amount of rain coming in probably 6 to 12 hours.” The region could face once-in-a-century rains and there is a good chance Nevada will break its all-time rainfall record, said the meteorologist Jeff Masters of Yale Climate Connections and a former government in-flight hurricane meteorologist.