The fiercest Caribbean storm in almost a decade ripped into Haiti's southwestern peninsula early on Tuesday with 145mph winds which left at least one person dead.
Hurricane Matthew, a Category 4 storm, pounded coastal villages on the Western tip of Haiti at 7am EDT (11am GMT).
One man died when a wave crashed through his home in the beach town of Port Salut, according to Reuters. He had been too sick to leave for a shelter. A fisherman is also thought to be missing.
Widespread flash floods and mudslides are likely in southern and northwestern Haiti, threatening villages as well as shanty towns in the capital Port-au-Prince, where heavy rain fell overnight.
There are fears that many of Haiti's poorest people are unable to evacuate, because they lack resources to move or a place to go.
Christian charity Compassion has worked in Haiti since 1968. It currently supports more than 94,000 children there.
Haiti country director Guilbaud Saint Cyr yesterday called on all Christians to pray.
"Pray that God, who has control over the hurricane, slows it down, minimises its threats, and keeps the nation safe," he said. "Pray for enough provision for the eventual victims and affected people. Pray for the Haitian government and authorities to make the right decisions to help the people who might be affected."
The hurricane means yet more disruption and potential loss of life for Haiti, the poorest nation in the Western hemisphere.
In January 2010 an earthquake killed more than 200,000 people. Rebuilding has been blighted with problems and six years on, tens of thousands of people still live in tents. Cholera introduced by UN peacekeepers is expected to rise in the October rainy season.
Haiti has been unstable politically for most of its history. A long-postponed election is due to be held this Sunday (October 9).
Saint Cyr said the poorest people in Haiti were the most vulnerable:
"[They live] in tents, near ravines, etc, and in times of hurricanes like this, they lack everything. This includes shelter, food, water, dry clothes and hygiene items."
He said Compassion's field office and church partners had identified families most at risk from the hurricane and were helping to relocate them.
Part of Compassion's ongoing work in Haiti involves disaster and crisis response for churches and families. To support this work by sponsoring a child in Haiti, visit Compassionuk.org