"It was an intense night for everyone in Bilwi, Waspam and the communities along the northern coast," Yamil Zapata, local Bilwi representative of the ruling Sandinista Front, told local Channel 4.
Guillermo González, director of the country's emergency management agency, said in a news conference that there were reports of corrugated metal roofs flying off homes, trees, poles and power lines falling and rivers rising in the coastal area. So far, there were no reported injuries or deaths, he said.
About 10,000 people were in shelters in Bilwi and an equal number in smaller towns across the region, he said. The area had already been lashed with strong winds and heavy rain for hours.
Authorities in Nicaragua and Honduras had moved people from outer islands and low-lying areas to shelters. Residents scrambled to shore up their homes, but few structures along Nicaragua's remote Caribbean coast were built to withstand such force.
Nicaragua's army moved red-helmeted troops specialised in search and rescue to Bilwi, the main coastal city in an otherwise remote and sparsely populated area.
At a shelter in Bilwi, farmer Pedro Down waited late Monday for Eta's arrival. "When it comes it can rip off all the (roof) and destroy the house, so you have to look for a safer place," he said, cradling a baby in his arms. "So I came here to save our lives."
Nicaragua Vice President and first lady Rosario Murillo appeared on television on Monday and prayed for God to protect the country. She said Nicaragua would apply lessons learned from previous storms. "How many hurricanes have come and we have moved on, thanks to God," she said.
Along Honduras' northern Caribbean coast, torrential rains from Eta's outer bands caused some rivers to overwhelm their banks Monday, forcing evacuations.
This could be only the beginning of Eta's destruction. The storm was forecast to spend much of the week meandering over Central America.
Forecasters said central and northern Nicaragua and much of Honduras could get 380-635mm of rain, with 890mm in isolated areas. Heavy rains also were likely in eastern Guatemala, southern Belize and Jamaica.
A storm surge of around 4.5m above normal tides was possible for the coast of Nicaragua, forecasters said.
The quantities of rain expected drew comparisons to 1998's Hurricane Mitch, one of the most deadly Atlantic hurricanes in history. An archival report from the National Hurricane Center said Mitch led to the deaths of more than 9000 people.
Eta tripled in strength in about 24 hours, rapidly intensifying from a 65km/h storm on Sunday morning to a 190km/h hurricane around midday on Monday, and continuing to gain power throughout the day.
It is the eighth Atlantic storm this season to hit the meteorologists' definition for rapid intensification — a gain of 56km/h in wind speed in just 24 hours. It's also the fifth to reach major hurricane status. Over the past couple of decades, meteorologists have been increasingly worried about storms that just blow up in strength.
Eta is the 28th named Atlantic storm this season, tying the 2005 record for named storms. It's the first time the Greek letter Eta has been used as a storm name because after the 2005 season ended, meteorologists went back and determined a storm that should have been named wasn't.
Hurricane season still has a month to go, ending November 30. In 2005, Zeta formed toward the end of December.
- Associated Press