A wildfire is shown burning near the Westminster highway on Department of Defense land in Richmond, B.C. on Friday July 27, 2018. The blaze broke out around 6 a.m. in bush and forest next to the Richmond Nature Park, a bog-forest area. THE CANADIAN PRESS/HO-BC Wildfire Service *MANDATORY CREDIT *

RICHMOND, B.C. - Officials say a wildfire that broke out early Friday in the Vancouver suburbs presents a more hidden challenge for crews than some of the blazes burning across the rest of the province.

Deputy Chief Kevin Gray of the Richmond Fire Department said on Saturday that because the fire is burning through a marshy wetland of dead plant life and moss, flames aren't necessarily visible above ground.

"The fire burns down in the peat, so down around the bases of some of the roots it'll burn holes," said Gray in a phone interview.

Those burnt-out roots can then create pockets in the ground called ash pits, which are well-hidden and can cause significant injuries to firefighters and anyone wandering in the area.

Gray said the ground around the pits can be deceptively soft and can run very deep, adding the initial fall may not be the worst outcome.

"With some ash pits we've seen them up to six feet (deep), so you can injure an ankle or a leg," he said. "Then with that fall, you fall over and put your hands into burning terrain."

Other than a few cuts, bruises, and splinters, Gray said none of the 60-person crew made up of the Richmond Fire Department, BC Wildfire Service, and Canadian Armed Forces members had sustained any injuries so far.

The fire's northern border is near Canadian Forces Base Colonel Sherman Armoury, and Gray said a dozen members of the Armed Forces stepped in to help the fight.

Gray said weather conditions Friday night were helpful for the crews battling the blaze, allowing them to continually drench potential kindling for the fire, such as dead grass and dry wood.

"We had crews off of the south end ... continuously flowing water off the street into the brush to protect any houses on the south side," said Gray.

Capri Alton works at the Island Veterinary Hospital, about one kilometre away from the wildfire. She said the smoke was significantly clearer when she arrived for work Saturday morning than on Friday.

"I'm looking out towards the bog right now and you can't see a distinct cloud, versus yesterday when you could see a distinct cloud of smoke," Alton said over the phone on Saturday.

She said none of the animals seemed bothered by the smoke, and the only complaint the office had received was the closure of the road south of the fire, which blocked one of their entrances.

Meantime, Metro Vancouver has issued an air quality advisory for eastern parts of the city and the Fraser Valley region — although it's not directly due to the fires.

"This advisory is for ground-level ozone, however there is a noticeable haze in the region which is due to a layer of wildfire smoke over the South Coast from distant wildfires burning in Eurasia and Alaska, as well as a bog fire in Richmond," a statement on the municipality's website reads.

"Wildfire smoke concentrations are not causing particulate matter objectives to be exceeded."

Gray said the crew is on schedule with their objectives for the fire.

"Overall we're managing it quite well," he said.

- By Spencer Harwood in Vancouver (Follow @SpenceHarwood on Twitter)

News from © The Canadian Press, 2018