A firefighter's pictures have shows the extent of "wildfires" that authorities say are often deliberately started and cause widespread damage.
Craig Hope posted pictures on Tuesday evening showing how close one fire on the Treherbert side of the Rhigos mountain road got to harming a flock of sheep.
It comes after a weekend when fire services pleaded with people to not start deliberate fires after they dealt with more than 500 grass and rubbish fires since March.
"Lucky escape for these sheep tonight", Craig wrote.
"Luckily the green grass under the trees didn't burn as they were surrounded!
"Another deliberate wildfire risking communities and damaging our environment", he added.
In one picture, sheep can be seen sheltering in amongst trees, in another they are walking across newly-burnt fields.
Craig Hope said the Rhigos mountain road fire pictured was fought by three crews, a specialist wildfire team who use fire to fight fire and a Natural Resources Wales helicopter.
He said 15 hectares were burnt in total, but they managed to stop it before the area of forestry.
Meanwhile, South Wales Fire and Rescue Service said it received reports of a large grass fire at the rear of Black Vein Industrial Estate, Wattsville.
Upon arrival, the crews were faced with a fire spreading quickly to affect 80 hectares of grassland and forestry.
Helicopter footage posted by the fire service below shows the extent of the damage.
It also made an appeal on social media for people not to use so-called "sky lanterns" to show support for the NHS.
Sky lanterns are kind of hot air balloon made from paper, fuelled by a naked flame.
Natural Resources Wales also said five fires that set sections of the Afan Valley and Seven Sisters forests ablaze caused over £100k worth of damage.
"At a time when the country is on lockdown because of the coronavirus pandemic, fire and rescue officers had to put themselves at risk to put the fires out", Natural Resources Wales said.
Three of the five fires are being investigated as suspected arson by South Wales Police.