Caritas Bangladesh and World Vision Bangladesh are packaging food parcels and blankets for people displaced by Cyclone Sidr, which struck on Thursday with wind speeds topping 100 miles per hour.
On Monday unofficial death toll estimates exceeded 3,000 people, while as many as 10,000 were feared dead.
Victims are mainly poor farmers, fishermen, and day laborers along the coast of Bangladesh, a Muslim-majority country of 140 million.
Caritas Bangladesh, the local Catholic Church's relief and development organization, has begun sending rice, lentils, salt, and oil to nearly 19,000 families, with clothing and baskets to follow.
"The loss of housing, winter vegetables and trees is huge in the affected area" said Benedict D'Rozario, executive director of Caritas
Caritas field worker Ananda Das said the most urgent needs are food and medical care.
World Vision Bangladesh, part of an international Christian humanitarian organization, plans to provide emergency food packs and emergency supplies to 20,000 families. They are also providing first aid to those hurt by falling trees or collapsed houses.
Before the cyclone made landfall, Caritas and World Vision personnel assisted other organizations and government officials in issuing storm warnings through bullhorns and moving people to storm shelters.
Some 600,000 people were evacuated from the southern coastal area.
Between 1985 and 1998 Caritas built more than 220 two-story shelters, while World Vision accommodated more than 20,000 people in its 31 cyclone shelters and schools that double as shelters.
Father Mrityunjoy Dafadar, parish priest of the coastal Shelabunia Catholic parish, told UCA News over the telephone that he hoped the Church and local government would soon bring help to the survivors. "Thirty cyclone shelters are full with thousands of people and hence contagious diseases may spread," he said, repeating the call for medical aid.
"Most of the poor people have lost their houses, either partially or entirely," he said, requesting housing for refugees.
Past cyclones in Bangladesh have been very deadly. A storm in April of 1991 sent a tidal surge that killed about 143,000 people, while in 1970 the deadliest storm on record killed around 500,000.
.- The worst cyclone to hit Bangladesh in a decade has united Catholic and Protestant aid organizations as they endeavor to aid the storm's victims.