Glacier Creek fire little cause for ongoing concern, says geotech report

A late-season forest fire north of Kaslo shouldn’t cause water quality or landscape stability issues in the future, says a report to the Southeast Fire Centre.

The Glacier Creek fire began on September 3 about 40 kilometres north of Kaslo, on the east side of Duncan Lake. It burned for about a month, and produced smoke into October, though limited growth was observed after mid-September.

The fire burned about 139 hectares of the nearly 28,000-hectare watershed.

“The fire burned only a very small portion (0.5 %) of the Glacier Creek watershed and no creek drains the fire area,” wrote provincial government geomorphologist Sarah Crookshanks. “Therefore, the likelihood of downstream impacts is negligible.”

The fire was located in steep, hard-to-access terrain, and was mostly just monitored by the BC Wildfire Service. It is listed as ‘under control’ by the forestry service.

Crookshank’s surveys try to predict the impact fires can have on future flooding and landslides that affect water quality, roads and other infrastructure in an area. (Her recent report on the Briggs Fire east of Kaslo also foresaw limited impacts from that burn.) She found only 0.6% of the area suffered a high-burn severity, while 11% was moderately burned.

“While the terrain is certainly steep to generate landslides, the incremental effect of the fire is low due to the low vegetation burn severity,” she states in the report.

She also determined a large 2007 landslide in the burn area was unaffected by the fire.

“The area immediately above this slide has patchy moderate soil burn severity and low/unburned vegetation burn severity,” she reports. “The likeliest time of year to see slide movement at this site is during the spring melt when the slope is saturated. Wildfire can increase snow accumulation and the rate of snowmelt through changes to the forest canopy.”

However, she notes that because the fire had minimal impacts to that canopy above the slide, “the incremental effect of this fire on movement at this site is expected to be low.”

That’s good news for one landowner in the area, she says.

“Given the low burn severity, lack of creek channels and no history of overland flow, there is a low likelihood that the wildfire will contribute to the initiation of a landslide that would impact this dwelling,” she says.

She also said the fire shouldn’t have any significant impact on drinking water quality or the campground that’s in the area.

Monument Creek hazard

Meanwhile, a report by Crookshanks on the Monument Creek fire northwest of Nelson, also released last month, found that residents who get their water from Duhamel Creek might face some degradation of their water quality at times in the future.

The September 4 fire burned about 440 hectares in the Duhamel Creek watershed and nipped the edge of the Lemon Creek watershed. While the Duhamel drainage has a history of floods and debris flows, the fire did not affect the most hazardous areas very severely. Thus, “it is improbable that a debris flow generated within the fire area would transition to a debris flood within the main Duhamel Creek channel,” the report states.

The report also recommends the Duhamel Face (Heights) road be closed, as it has a history of failure and the fire may have destabilized the road bed further.

“Evidence of potential instability was observed at one location,” she notes. “The burned area may increase the likelihood of landslides originating from this road.”

There was no mention in the report of any potential impact to the Lemon Creek watershed.

John Boivin, Local Journalism Initiative Reporter, Valley Voice