Surveying the aftermath of the flash floods which hit Arkengarthdale and Swaledale on the evening of July 30, they found 12 bridges washed away and over 3km of footpaths and bridleways destroyed. Grinton Bridge, which famously featured in the Tour de France Grand Depart back in 2014, was gone.
The once-in-a-generation freak weather event concentrated on a small corner of the Dales has left communities reeling.
For the 24 rangers who work across the park, they thought Storm Desmond in 2015 had caused the worst damage they would see during their careers.
Cost of Dales flooding for farmers likely to exceed £3millionBut the summer downpours - 113mm of rain fell in less than three hours - surpassed the infamous Christmas storms almost four years ago.
Alan Hulme is a former ranger who is now in charge of park management for the Yorkshire Dales National Park Authority, and he has been heavily involved in the clean-up process.
"We are in charge of maintaining the public rights of way, the paths and bridleways. So far we have counted 11 bridges and a set of stepping stones that are missing, and 3.5km of paths have either been washed away or covered in debris or landslips. These are key links within the park network and we have lost large sections of them - one path has been swept into a river.
Farming community speaks of devastation after flash floods hit Arkengarthdale"Storm Desmond affected the Howgill Fells in the west of the park, but this has been significantly worse for the Dales - it's unprecedented and was very localised to Arkengarthdale. It's been quite devastating - thousands of tonnes of debris have fallen on roads and paths. It's been a real team effort to get things moving again."
Alan has been impressed by how people have pulled together to repair the damage. A volunteer day organised by the Dales Bike Centre at Reeth saw 65 people, many of them mountain bikers, turn out to shift 150 tonnes of debris from a bridleway at Langthwaite, close to the flooded village pub. Other groups have repaired stiles and drystone walls.
He met Douglas Barningham, the farmer who was the subject of media attention when he released CCTV footage from his barn showing his daughter's pony, Crunchie, swimming to safety after becoming trapped by rising waters.
Shocking photos show extent of damage to Tour de France Grand Depart bridge at Grinton"His car was lifted out of the barn - the sheer power of the water was amazing. I've been amazed by the resilience of the locals, and at the efforts of the volunteers, who have turned out in droves. Farmers tend to be very independent by nature but this has taken them by surprise.
"In the short term we are getting back to normal, and looking to get the rights of way back into use. There is government funding for flooded businesses but nothing for us, and we expect the cost of footpath repairs to be around £1million. In future we need to look at catchment management and how the flow from the dales into the rivers can be slowed down.
"These extreme weather events seem to be happening more regularly - it's a once-in-1,000-year event for one place, but the number of intense flash floods seems to be increasing."