Sheep Mountain’s sheep will have to accustom themselves to explosions, dust and falling rock shards while the Alaska Highway is widened this summer.
The construction proposal, which would widen the highway and smooth out some of its curves, is currently undergoing an environmental assessment through the Yukon Environmental and Social Assessment Act.
However, work is expected to be given the nod, said Allan Nixon, manager of environmental affairs for the Highways Department.
The job is expected to begin in June and will wrap up sometime in October. It will be completed over two seasons.
“I’d be surprised if it was turned down for some reason, but it has to go through the process,” said Nixon.
The Sheep Mountain stretch is the final leg of the Shakwak Project, which has been rebuilding the Alaska Highway since the late 1970s.
The project is being paid for by the US government, but is managed by the Yukon government.
“Basically it involves widening of the existing highway and softening some of the curves and improving site distances, and whatnot, through that section,” said Nixon.
“This is our last piece (of highway) for a couple reasons; for one, it’s probably the most challenging in terms of engineering that had to go into it as well as the environmental issues, and also just the interest that people have in the area.
“So it’s kind of been working from both ends toward Sheep Mountain for several years and we’ve been looking at options and what we could do and how we were going to build it — looking at that over the last several years, and we’ve come down to a final design and a plan that we think is probably the optimum for what we’re dealing with here.”
The Highways Department has identified the area’s sheep as significant and valuable, and has taken steps to mitigate the impact the blasting and highway work will have on the animals.
Even though traffic patterns would suit the project proceeding during the winter, it is being done during the summer months because the sheep are at a higher elevation at that time.
The spring and summer months are the best time to undertake blasting work on the rock face of Sheep Mountain, said Jim Pojar, executive director of the Canadian Parks and Wilderness Society’s Yukon chapter.
“It is a reasonable time, in the sense that it’s after lambing and it’s before breeding, which is in the fall, and it’s not during winter when they are under stress from the climate and cold and lack of food, but just the loud noise of a blast might cause them some anxiety,” said Pojar.
However, during the highway work the area’s indigenous rare plant species will be disturbed, which could allow weeds to spread, further upsetting the ecological balance.
“Especially with climate change, you can get some really bad weeds come in and invade the open habitats rather than the forest and, of course, Sheep Mountain has got a lot of open, grassy, habitats — that’s where the sheep like to be, especially in the winter,” said Pojar.
“There’s a danger of some of these (weeds) getting into the natural habitats and upsetting things … especially if sheep won’t eat them.”
The Highways Department’s plan is to do most of the blasting away from the rare plant species so they won’t be disturbed, said Nixon.
He doesn’t see the need to re-vegetate the area with native plant species, but if there is a need to do so after the work on the highway is finished, it will be done, he said.
“With respect to Sheep Mountain — I don’t often say stuff like this — it’s definitely unique in the world,” said Pojar.
“There’s lots of really interesting places in the Yukon, but there are few of them that are one-of-a-kind and Sheep Mountain is one of a kind because of the way it’s located in the lee of the big ice fields and is subjected to really strong winds that come down the Slim’s River valley … it’s about the driest, windiest place in the Yukon and that makes it perfect habitat for sheep.”
The sound of the blasts probably won’t disturb the sheep, said consulting biologist Manfred Hoefs.
He is more concerned with the flying rock possibly hitting the nearby sheep.
“I was most concerned about sheep getting hurt by flying rocks,” said Hoefs.
“The blast will not be too bad because the direction of the noise will be towards the lake.
“They are used to noise; they put up with rock slides and avalanches. The flying rock, I think, would be the problem.”
Hoefs also fears that blasting into Sheep Mountain’s steep rock face will make it even steeper.
When the sheep come down near the road, they might not be able to climb back up the rock face quickly enough, he said.
“They do come down on the road occasionally and sometimes they cross the road and lick salt off the road in the winter – and if traffic comes specifically from both sides, they are sort of in a bind; they want to get back on the mountain but they can’t because of the steep rock face,” said Hoefs.
“What I suggested was to build escape routes, building into the rock a sort of path to go up and have places where it’s a little bit wider and they could have several sheep there.
“That’s a serious problem and we have lost sheep there already to traffic accidents and that will become worse if precautions aren’t built into the plan.”
There are plans to build escape routes and trails for the animals should they be needed after the blasting is completed, said Nixon.
The mountain’s Dall sheep range from white to slate brown and have curved, yellowish-brown horns.
Dall sheep are found in relatively dry country and try to remain on open alpine ridges, meadows, and steep slopes with extremely rugged ground in the immediate vicinity, in order to escape from predators.
Males live in bands, and seldom associate with female groups except during the mating season in late November and early December.
Lambs are born in May.
During the summer when food is abundant, the sheep eat a variety of plants.
In winter their diet is limited, consisting of dry, frozen grass and sedge stems, available when snow is blown off. They also eat lichen and moss.