Hurricane Hermine has made landfall over northwest Florida in the United States. It's the first hurricane to directly strike the Sunshine State in more than a decade. 

The US National Hurricane Center says Hermine made landfall early on Friday, causing damage and leaving tens of thousands of households without power along Florida's Gulf Coast. The state governor declared a state of emergency in 51 of Florida's 67 counties, and at least 20 counties closed schools.

The UN disaster agency says Hurricane Hermine is "the most severe test of disaster resilience" for the US since Hurricane Sandy in 2012, and economic losses will undoubtedly be significant.

"This is the first hurricane to make landfall in Florida in the last 11 years, and it is probably the most severe test of disaster resilience in the United States since Sandy four years ago," said Denis Mcclean, spokesman, UN Disaster Reduction Agency.

"We already know that storm surges of up to four meters are expected, together with 50 centimeters of rain."