MIAMI (AP) — Of the 660,000 people facing mandatory evacuation orders in Miami, the city’s homeless population is particularly difficult to move into shelters.

Many of the city’s estimated 1,100 homeless people live in waterfront parks and other places where Hurricane Irma could be most deadly.

The Associated Press joined a crew of social workers and police who are giving the homeless a stark choice: either come willingly to a shelter, or be held against their will for a mental health evaluation.

The “Baker Act” is normally invoked to put people who pose a danger to themselves or others in psychiatric wards. It enables the state to detain people for 72 hours.

By then, Hurricane Irma will be somewhere north of Miami.