The rivers Chari and Longone, which run between the two countries, had burst their banks following the heaviest rains in more than 30 years.
According to reports from mission partners on the ground, the damage caused was catastrophic.
The floods were yet another blow to Christians on both sides of the rivers.
Many of these Christians were already suffering because of repeated attacks on their communities by Islamist militants.
But thousands of these destitute Christians rejoiced to see trucks laden with essential supplies drive into the villages in which they were seeking refuge.