A Strategy For Avalanche Control Around Mountain Goats in Northwest BC
By Steve Brushey, District Avalanche Supervisor, Northwest Avalanche Program, and
Amanita Coosemans, Senior Ecologist, Balanced Ecological Management Company
This article was originally published in The Avalanche Journal, Volume 129, Spring 2022.
INFOEX IS AN INTEGRAL PART OF ALMOST every Canadian avalanche program’s daily routine. The premise of InfoEx is about keeping your nearest neighbours informed of what you’re seeing with respect to weather, snowpack, avalanche occurrence observations, avalanche summaries, and avalanche hazard.
The BC Ministry of Transportation and Infrastructure’s Northwest Avalanche Program, which is based in Terrace and covers several northern highways, shares information almost daily with roughly 22 operations. However, in the Skeena, Nass, and Bowser corridors, there is one neighbour that doesn’t share or provide information but can be negatively impacted by our daily operations. This operator can be challenging to see, yet operates year-round in the same mountain environment.
This past year, after discussion with the Ministry of Environment, our program commissioned a biologist to develop a goat mitigation strategy. Certainly, many provincial operators have goat mitigation strategies, some that are more robust than others, but our program operates in one of the foremost goat habitats in British Columbia, in particular the south aspects of the Skeena and Nass River corridors. We encounter goats on a regular basis as most of our work takes place on southerly aspects, and we have modified control missions and field work on numerous occasions due to wildlife. It was time for us to consider our silent neighbour.
This article presents an adaptive strategy for working around mountain goats. It describes relevant background information on mountain goats and their habitat, and discusses the known effects of specific disturbance types. This background knowledge informs the presented suite of options, methods, and protocols that can be used to reduce or avoid harmful effects on goats during essential avalanche control activities.
GOATS AND THE LAW
Most of the world’s mountain goat population lives in British Columbia. Goats are scattered throughout nearly all of the province’s mountainous terrain, with most found in the northwest portion of the province. Mountain goats are a blue-listed species in B.C., meaning they are vulnerable because their populations are particularly sensitive and because human activities may put individuals and populations at risk.
B.C. protects mountain goat populations and their habitat through a range of legislation, guidance documents, and best management practices . The BC Wildlife Act deems it illegal to herd or harass wildlife. The legal definition of harassment in the act includes, “Worry, exhaust, fatigue, annoy, plague, pester, tease or torment.”
WINTER RANGE
Winter habitat is the part of the home range used for the longest duration in the year and is considered the most important habitat given how difficult it is to survive during the winter season. Winter means reduced access to food and higher energy costs. In winter months, mountain goats inhabit windblown slopes or ridges that have sufficient food and warm (south or west) exposures. They also move to lower elevations where the snow is not as deep and more food is available. Ready escape terrain such as rocky outcrops, cliffs, or bluffs within 400 m is important in winter ranges as escaping predators is more difficult in snow.
Winter range may include a variety of habitats that, together, provide accessible food, protection, and relative ease of mobility. For example, snow-shedding, south-facing slopes may provide forage and escape terrain, while nearby old-growth forest areas provide thermal and security cover, reduced snow depth, and access to arboreal lichens and understory vegetation.
FLYING AROUND MOUNTAIN GOATS
The critical period for mountain goats is from mating to kidding, which is roughly November 1 to June 15. During this period, goats are physically stressed and vulnerable. During the late-winter and kidding periods, disturbance to goats increases mortality and reduces births. Virtually all subalpine and alpine terrain in British Columbia should be considered goat habitat at all times of year.
Mountain goats are considerably more sensitive to human disturbance than other ungulates, and show a particular sensitivity to aerial disturbances. Disturbance effects can be particularly difficult to observe in this species as mountain goats frequently do not show a flight response. Still, individuals and populations respond negatively to disturbance over the longer timeframe by showing increased mortality, reduced fitness, and reduced kidding rates. Females with kids appear to be even more sensitive to disturbance than other adults.
When goats are in the safest or best habitat around, or if snow is too deep, they may tolerate disturbance, but still be stressed. Goats are often described as “habituated” to disturbance, but evidence shows this is rarely the case, particularly when disturbance stimulus is strong and unpredictable and/or irregular. In fact, goats may instead become sensitized to disturbance, meaning their stress level increases with each subsequent disturbance event.
Mountain goats are easily disturbed by low-flying aircraft—especially helicopters. Low-level flights cause physical and emotional stress, which increases indirect and direct mortality in both the immediate and longer term. Impacts from helicopters and other human disturbances such as aircraft, avalanche control, and field work depend strongly on the timing (season), frequency, and duration of disturbance.
For helicopters, in particular, flying distance is the key factor affecting the degree of disturbance. Behavioural responses range from increased vigilance and wariness at farther distances, to severe fright or flight responses at close distance.
Extensive scientific research supports helicopter buffer areas on the order of two kilometres horizontal distance and a vertical separation of 400 m. Decreased distances sharply increase stress responses and strong to extreme stress responses are common within 500 m horizontal distance of helicopters.
AVALANCHE CONTROL IN GOAT HABITAT
Avalanche control work is clearly different from other industrial, commercial, or recreational activities in mountain goat habitat. For public safety, it is understood that goats will, in some cases, need to be disturbed during the critical period. Where no other options exist, it is preferred to herd goats away from an avalanche zone rather than to allow them to remain in the direct line of danger. This can be done by
approaching carefully with the helicopter and attempting to move them out with a slow and gradual approach. As every avalanche control area in the province is unique, an adaptive approach is required to mitigate and minimize negative impacts to mountain goats in their winter habitats.
When undertaking avalanche control work, helicopters are often obliged to fl y close to or within active goat habitat during the critical winter period. Advance planning and communication with teams and pilots for flights and control activities can dramatically reduce harm to mountain goats. Where flights within two kilometres horizontal distance or 400 m vertical separation are necessary, pilots can use several strategies to reduce stress and potential harm:
- Absolutely no explosive training in goat sensitive areas.
- Is avalanche control essential? Consider other options.
- Know where goat habitat is located and plan around it wherever possible (e.g. flight path).
- Whenever possible, maximize separation distance from goats, particularly if they are reacting to disturbance (ideally >2 km horizontal distance and/or >400 m vertical distance).
- Keep helicopters below mountain goats; approach from below every time.
- Use topographic barriers to separate helicopters from mountain goats.
- If unavoidable, travel at low speeds, particularly when approaching animals.
- When avoidable, do not fly directly towards, hover near, or land near mountain goats.
- Minimize the number of flights and time spent within disturbance space.
For most helicopter-based activities, it may be possible to completely avoid disturbing mountain goats year-round using two simple strategies:
1) Stay at least two kilometres (horizontal distance) from mountain goats and their habitat.
2 )Maintain at least 400 m vertical distance from mountain goats and their habitat.
While the nature of avalanche control activities means that disturbance cannot be completely avoided, good route planning with the helicopter pilot to the avalanche area will reduce negative effects on goats using other nearby winter ranges.
An adaptive approach will inform how avalanche control is done, ideally reducing impacts to goats over time as better approaches are developed. For areas that are known to be of high risk, or that have high mountain goat values such as the south aspect of the Skeena River corridor (i.e. a significant population concentration, presence of kids, or struggling population), consult a biologist for developing specific mitigation plan for these areas.
