The Ross River School’s structure is in critical condition, likely due to shifting permafrost, according to an engineering firm that assessed the building last week.

The major cause of that movement is the “extremely high” temperatures in the school’s crawl space, Stantec Consulting Ltd.’s Jan. 16 draft report notes.

The school, built in 2001, closed down indefinitely last Sunday for the second time in just over a week.

The first closure was announced Jan. 9, after cracks were discovered in some of the walls.

The Department of Highways and Public Works hired two independent engineering firms to check out the structure.

“Those assessments determined that the cracks did not indicate significant structural issues with the facility and, as a result, the two engineering firms indicated it was safe for occupancy with no immediate threats to safety,” department spokeswoman Kendra Black said Monday afternoon.

But after more thorough investigation of the school’s walls, floors, foundation and roof, one of the firms submitted its draft report last Friday.

It determined that the building had structural deficiencies and flaws, likely due to shifting permafrost, and that in the event of adverse weather, like a major snowfall, strong winds or seismic activity, the school could become unsafe.

It noted the 17 C temperature in the building’s crawl space – with a heating system like the school has, it’s generally required to keep the crawl space temperature the same as the outside air.

The school’s main floor is uninsulated as well.

“Normally, this is not a structural concern, but in this case, heat escaping into the crawl space is considered to be promoting permafrost degradation,” Stantec’s structural engineer writes.

The report recommends the crawl space area should be left unheated in the future and the main floor area be insulated.

But Black said this morning the space has to be heated because of pipes and equipment stored there.

Dating back to 2011, she said the crawl space has been kept at a temperature of 16C and higher.

“We insulated the crawl space to minimize the heat transfer to the permafrost,” Black said.

Stantec’s report includes photos of the problem areas: sloped floors, gaps between walls and floors, broken windows due to shifting walls, broken foundation piers, and a long crack in the lobby floor.

One concern noted in the report is that movement of the walls can cause “undue stress” on mechanical and electric pipes and ductwork, which can lead to fire and environmental hazards.

“Failure of mechanic and electrical components are highly possible given the extent of movement this building is experiencing,” it states.

Black said although the department understands there’s a low risk of immediate structural failure, the possibility for that to happen in the future, in inclement weather, was enough to prompt the closure.

“We’re not prepared to accept that risk, and therefore we’ve closed the facility,” she said.

About 50 students from Kindergarten to Grade 10 attend the Ross River School.

Yukon College’s Ross River Dene Cho Kê’endį campus also runs classes out of the building. Roughly 50 college students and instructors are affected by the closure.

An alternate location has not yet been found.

Community meetings have been held in Ross River over the past two days, involving parents, teachers, students, government officials, and the chief and council.

The purpose has been to discuss possible options: search for existing facilities in town, bring in temporary facilities, like trailers, or bus students 75 kilometres to Del Van Gorder School in Faro.

“We’re still in the process of getting feedback from the community,” Ronuk Modha, a Department of Education spokesman, said this morning.

Ross River Dena Council Chief Brian Ladue could not be reached for comment before press time this afternoon.

The Stantec report doesn’t estimate the costs to fix the school, but states “significant work” will be required.

It will be necessary to relevel the building, fix or replace broken foundation piers, and investigate the mechanical and electrical systems to make sure they weren’t damaged by the shifting, the assessment states.

Black said the building has been monitored over the years because of its construction on permafrost. Cracks have been spotted before in walls and weren’t found to be a safety risk.

But when new, “significant” cracks were located in the school walls earlier this month, Black said, the department requested the engineering assessment planned in the near future be conducted sooner and more thoroughly.

She said there isn’t yet a timeline in place for when the school will be repaired and reopened.

A geotechnical assessment and further investigation will have to be done, she said.