"Hell on earth – that is how one evacuated resident described the massive fire burning in Fort McMurray, Canada," wrote Franklin Graham this week.

"It's a raging fire that is 25 per cent larger than all of New York City. Some 100,000 people have been evacuated and over 1600 homes and buildings have already been destroyed. Over 600 square miles have been consumed, and officials say it could be months before it is totally brought under control. It's so large there are even reports that you can see the smoke from as far away as Florida. Many families had to evacuate at a moment's notice not knowing if their home or neighborhood would still be standing when they returned."

Graham, who heads the Billy Graham Evangelistic Association and Samaritan's Purse, announced on his Facebook page that Billy Graham Rapid Response Team chaplains are being sent to minister and pray with individuals.

Samaritan's Purse Canada will also be deploying disaster response teams and volunteers to help residents with clean-up as soon as people are allowed back into the areas.

"Pray for the all those whose lives have been turned upside down and those who have lost everything. And join me in asking God to protect the heroic firefighters battling this dangerous blaze," Graham wrote.

Samaritan's Purse is appealing for volunteers and is liaising with local churches to be ready to help as soon as the fires are brought under control and the evacuation order is lifted.

The charity helped in 2011 after similar forest fires in Slave Lake, Alberta destroyed more than one-third of the town.

Work needing to be done includes sifting through the ashes of destroyed or badly damaged homes, searching for personal items and what can be salvaged and removing debris.

In Salve Lake, the charity helped remove and empty fridges and freezers that had no electricity for several days, and well as pressure-washed homes to remove soot and ash or fire-suppressant stains.

The Billy Graham Evangelistic Association of Canada has been invited to be part of the team offering emotional and spiritual care at two of Calgary's reception centres which are providing shelter to displaced Fort McMurray residents. Brent Davis, Samaritan's Purse Disaster Response manager, says a response team will be on the ground in Fort McMurray as soon as it is possible to enter the city, said: "We know the entire community of Fort McMurray is going to be impacted by this fire, physically emotionally and spiritually for months and years to come."