Hurricane Felix has hit Nicaragua's north coast as a category-five storm, the highest level, but weakened to a category one as it moved over land.
About 12,000 people have been evacuated from the coastal areas
Winds of 160mph (260km/h) lashed coastal areas, tearing off roofs and uprooting trees and electricity lines.
Thousands have fled the area, but many indigenous people are said to be stranded on the Honduran border.
Meanwhile, Tropical Storm Henriette reached hurricane strength as it hit Mexico's Baja California peninsula.
The Mexican government declared a state of emergency in the southern region popular with tourists, as the storm's top winds increased to 85mph (140km/h).
The category-one hurricane was expected to track across the peninsula and into the Sea of Cortez overnight.
Henriette caused landslides in the Mexican city of Acapulco at the weekend that killed six people. One woman drowned in high surf in Cabo San Lucas on Monday.
Felix is the second category-five storm to hit the region in less than a month. Two weeks ago, Hurricane Dean killed 18 people.
It is the first time two category-five hurricanes have hit land in a season since 1886, according to the US National Oceanic and Atmospheric Administration.
There have been no reports of any fatalities from Felix. However, local officials said two fishing ships carrying 35 crew had gone missing off Nicaragua.
The Miami-based National Hurricane Center (NHC) said the storm could dump up to 64cm (25in) of rain in isolated parts of northern Honduras and north-eastern Nicaragua, possibly bringing flash floods and mudslides.
An official in Bilwi (formerly Puerto Cabezas), Lumberto Campbell, described the scene as the storm hit.
"The wind is terrible. There's a roaring when it pulls the roofs off the houses," Mr Campbell was quoted by the Associated Press news agency as saying.
"There's no electricity because all the posts that hold up the cables have fallen down."
Nicaraguan President Daniel Ortega has cut short a visit to Panama to lead emergency efforts.
Hundreds of tourists have been evacuated from the islands of Honduras, while both Honduras and Nicaragua have been evacuating Miskito Indians who live along the coast on either side of the border.
Indigenous people of Central America
Live in lowlands along Nicaragua's Caribbean coast, also in Honduras, Belize
Overall population estimated at 150,000
Culture influenced by contact with Europeans since mid-17th Century, inter-marriage with escaped Africans slaves
Communities extremely poor, mainly subsistence agriculture
But there are reports of transport problems, and many of the indigenous population are thought to be stranded.
A storm surge of 6m (18ft) above normal levels would be highly dangerous for those living in isolated coastal swamps.
On Sunday, Felix struck Aruba and two of the Netherlands Antilles islands near Venezuela - Bonaire and Curacao - but damage appeared slight.
The sixth named storm of the Atlantic hurricane season, Felix demolished a concert venue when it hit Grenada on Saturday.
The Atlantic hurricane season is expected to peak on 10 September.