Rescue crews worked through a second consecutive night on Wednesday, ferrying residents from rooftops and upper floors along the Cardenas Delta after three days of relentless rain sent the river more than four meters above its normal level.

Local emergency services said more than six thousand people had been moved to shelters by nightfall, with several outlying communities still unreachable by road. Fictional regional officials described the flooding as the worst the delta has seen in at least a generation.

“We have boats going door to door because there is no other way in,” said a civil-defense coordinator managing the response from a staging area outside the town of Marejo. “People are being remarkably patient, but patience doesn’t keep a house dry.”

The rain has eased somewhat since Tuesday, but forecasters warn that saturated soil upstream means river levels could stay elevated for days even without additional storms. Engineers are also monitoring a decades-old levee near the delta’s mouth that has never been tested against water this high.

Aid groups have begun distributing food and clean water at collection points, though several described difficulty reaching the most isolated households. “The roads that would normally get us there are the roads that are underwater,” one volunteer coordinator said.

Authorities have not yet given an estimate of when residents might be able to return home.