The rivers have been swelling for weeks in Brazil’s Amazon region, and residents in a town that bills itself as "The Venice of Amazonas" traded motorcycles for canoes and are clambering atop fresh-laid planks inside their homes to stay dry.

Anama, home to 14,000 people on a tributary of the Solimoes River that flows toward capital Manaus, is just one municipality of dozens in Amazonas state that has seen life upended by unusual rainfall.

Amazonas’ civil defense secretariat warned the flood could soon be the biggest recorded in the last century.

The secretariat said 350,000 people have already been affected.

As the river continues rising, the sound of power saws in Anama is constant as residents cut boards and beams to build rudimentary scaffolding within their homes.

It’s a race to stay above the water’s surface. Motorcycles are stored atop the wood, too.

“What we’re living isn’t good. The flood is here, in this home,” said Luzia Santiago da Costa, a 62-year-old homemaker.

Her knee problems mean she keeps her eyes focused on her steps while balancing atop the wood and moving slowly through her home.

Raimundo Sampaio Sobreira, 63, said his floor is now so high that he’s begun hitting his head on the ceiling.

“We are accustomed here, but this is going beyond the limits,” Sobreira said.

Twenty of Amazonas’ municipalities are in a situation of emergency, and 22 have rivers spilling over their banks, according to the secretariat's statement.

The latter group includes capital Manaus, where people have built makeshift bridges.

The Negro River, which flows past Manaus to meet the Solimoes River, could reach its highest-ever level within days, the state’s government said this week.

Increased precipitation is associated with the La Nina phenomenon, by which cooler-than-normal sea-surface temperatures in the central and eastern tropical Pacific Ocean impact global weather patterns.