One member of the aid relief group, Team Rubicon UK, has compared the aftermath of the tsunami in Indonesia to "like there's been a bomb".
Five team members flew out from the UK to Indonesia on Christmas Day to help communities in the Sumur region.
At least 400 people were killed when a volcanic eruption sent two waves up to five metres high surging into the Sunda Strait on 22 December.
Former WO2 in the Royal Fusiliers Regiment, Paul Taylor, has been a part of Team Rubicon UK for the last three-and-a-half years.
Mr Taylor, Operations Support Manager, spoke to Forces News from a seaside town where he described the scene: "There's a coastal road and there's houses on the other side of the road, back to a distance of about 250/300 metres, and everything has been completely flattened.
"For those who are from a military background, it's like there's been a bomb put on top of it, everything is completely flattened.
"There's just piles of rubble, piles of timber, depending on what method they used to build their house."
Team Rubicon UK, who are totally self-sufficient, are helping with recovery operations, assessing damage with drones and providing clean drinking water for 500 people.
Retailer Amazon and Mpowered have donated 2,000 solar lights to the relief effort, with Team Rubicon UK travelling to Jakarta in the coming days to help with the distribution.
The team deployed to Palu in Indonesia in October last year to provide help and expertise following the earthquake and then the consequent tsunami.
But Mr Taylor, who helped in Palu, says this tsunami has left less damage as it was not triggered by an earthquake, affecting just those along the coast.
Mr Taylor says the team will remain in the area for the foreseeable future: "We're out here for another couple of weeks at least, then we'll take it by a post-by-post basis.
"If we need to stay, then we'll stay and hopefully bring some more people in."