Crews need to spend at least two more days pumping water from a reservoir to stop its dam bursting and flooding a town, firefighters have said.
Whaley Bridge residents are spending a fifth day out of their homes because of the partial collapse of the dam wall.
Toddbrook Reservoir is 48% full but needs to drop to 25% before the 1,500 people evacuated can go home.
The dam is said to be “relatively stable” after four days of efforts to bolster it.
Crews using 23 high-volume pumps have removed more than a third of the reservoir’s water since part of its spillway collapsed on Thursday following heavy rainfall.
RAF Chinooks have dropped more than 500 tonnes of aggregate into the damaged section of the wall to reinforce it.
Forecasters had warned 30-40mm (1.2-1.6in) of rain could fall in two hours on Sunday night.
However, as many parts of the UK were hit with storms, Whaley Bridge saw only light showers.
Speaking late on Sunday, Wing Commander Coles said: “I think the assessment is now that actually the dam is relatively stable.
“It’s very much a case of pumping more water out, and those engineers when it comes first light, will make another assessment of how successful that’s been.
“The military will stand by ready to come back up if required but I think the sense of the moment is very much we’ve got through the worst of it.
“We were fortunate with the weather.”
Police, the Environment Agency, and the Canal and River Trust have all said there is still a “real risk” the 188-year-old structure could collapse and flood the town.
Meanwhile, 22 residents from 16 households have refused to leave their homes, prompting sharp criticism from police.
That number is down from 31 people in 22 homes, reported by police on Sunday.
Lives at risk
Deputy Chief Constable Rachel Swann said: “We’ve not evacuated this for no reason.
“We’ve evacuated this because there is a real prospect that the dam could fail, and if it fails it is catastrophic.
“People would die if they were in that evacuation zone. So those people who remain in that zone are putting their lives at risk.
“They are also putting the lives of the responders, primarily the police, at risk because we have to keep going in and speaking to them and asking them to leave.”
Labour leader Jeremy Corbyn is set to meet residents and emergency workers in the Whaley Bridge area later.
It follows Prime Minister Boris Johnson’s visit to the area on Friday.
The authorities have yet to reveal how long the evacuation zone will remain in place, but at a meeting on Sunday police said the “worst case scenario” was a week.
Speaking on Sunday, BBC correspondent Danny Savage said that within 48 hours the authorities could be thinking about moving people back into their homes.
Monday’s forecast for the area is for largely dry weather, with the odd light shower.