Blizzards
Blizzards combine high winds (typically in the 90 to 130 kilometres per hour range), blowing snow and low temperatures. The effects of the storm are always intensified by the wind chill factor associated with high winds. Blizzard conditions are often most severe in non-forested areas where there are no trees present to act as wind breakers.
Climate Change
Earlier snow melt in the spring and decreased water flows through the fall resulting from an increase in mean annual temperature may impact municipal water supply. Exaggerated glacial retreat is also a potential impact with increased ambient temperatures. This could result in an increased influx of fresh water to the Revelstoke area leading to a risk of flooding.
Heat Waves
It is important to note that there has been a tendency for both extreme and average monthly temperatures to increase slightly over time, which suggests that heat waves may become a more significant risk in the years to come.
Ice Storms/Ice Fogs
Ice storms can be more frequent in this region than in milder areas of British Columbia. Additionally, the disruption of transportation systems, communications and other infrastructure can have very serious and potentially fatal consequences.
Lightning
On average there are 6 days per year with lightning and thunderstorms in the area. Therefore, it is reasonable to expect lightning strikes to occur in and around Revelstoke more than once a year. However, the extent of damage caused by lightning will depend on what is hit and how quickly response agencies can recover from ensuing problems. A lightning sparked forest fire is a reality experienced by many areas and is a possibility in the surrounding areas of the City.
Snowstorms
Transportation to Revelstoke may be interrupted or delayed due to heavy snowfall and low visibility. Dangerous driving conditions due to white out conditions can cause motor vehicle accidents as a corollary effect of inclement weather. As well, extreme weather may cause disruptions to air transportation services. These incidents combined may be sufficient to burden local response agencies such as highway rescue, fire, police, ambulance and public works.
Avalanches
Small snow avalanches may occur in unpopulated areas in and around Revelstoke. However, the greatest avalanche risk to communities derives from the blocking of ground transportation routes. Highway #1 east of Golden periodically experiences closures due to avalanche danger.
Landslide / Debris Flow
The Columbia River creates a vast valley in between the Monashee Mountains and the Selkirk Range, both of which consist of metamorphic rock. According to the Ministry of Energy, Mines and Petroleum Resources, this type of rock is prone to rock slides and slumps. Landslide and debris flows are a persistent threat and especially for the Trans-Canada Highway which is the major access route to the City.
Seismic Event
The Revelstoke area is not located within an extreme earthquake zone and large magnitude earthquakes are rare occurrences. However, the area may be indirectly affected by damage to other provincial zones. Outside suppliers such as food delivery, may be unable to offer services, forcing the local community to face delays.
The area is relatively remote and accessible by railroad and the Trans Canada Highway, both lying in the east west direction. With both primary access routes coinciding, an earthquake could impede delivery of essential services and goods to the area.
Volcanic Ash Fallout
The Revelstoke area is not in immediate danger from volcanic activity; however, the potential for major volcanic activity exists for most of Western Canada. As well, a major volcanic eruption elsewhere has the ability to indirectly affect the area. Non-local suppliers, such as food and medical deliveries may be unable to offer services, which can result in shortages and long delays.
Flooding
There are complex hazardous flood prone areas primarily focused within the boundaries of Revelstoke. These areas are complex due to the creation of the Arrow Reservoir when BC Hydro constructed the Hugh Keenleyside Dam in Castlegar.
BC Hydro has constructed dykes in the Big Eddy and South Revelstoke, protecting low-lying land. While the dykes may protect land from direct floodwater, a rise in groundwater may occur due to high water levels. This may impact resident's basements and septic tanks. Dyke breaching remains a concern within floodplain areas.
Water levels in the Columbia River are regulated from the Mica and Revelstoke Dams thereby limiting any resultant flooding. However, should there be a dam breech, flooding poses a serious concern.
Tsunamis
The area can be affected by local terrestrial tsunamis. Local terrestrial tsunamis are most often caused by slope failure though on rare occasion can be caused by an earthquake-induced landslide. The Downie Slide north of Revelstoke has been identified as having potential for this type of event.
Wildland Fire
Wildfires rank among the threats of highest concern to municipal fire officials and the BC Forest Service. Generally, from May to October of each year, many areas of British Columbia can face a serious threat from interface wildfires.
While the cooler environment of Revelstoke may be less susceptible to wildland fires than the province's interior, occasional periods of high temperatures, low humidity, and high winds may exacerbate the risk. The area is relatively remote and accessible by railroad and the Trans Canada Highway, both lying in the east west direction. With both primary access routes coinciding, a wildland fire could impede delivery of essential services and goods to the area.
Wildland - Urban Interface Fire
Abnormally hot, dry weather and excessive fuel loading often make forest areas particularly vulnerable to lightning strikes and human carelessness. Once burning, a wildland fire can spread quickly due to high winds and easily overwhelm the capacity of local response agencies. Aside from the environmental and economic impact, wildland fires become particularly devastating when they encroach upon human settlements and critical infrastructure. When this occurs, they become interface fires and because of their difficulty to manage, can be extremely destructive.
Pandemics
Yearly epidemics cause serious illness and death, especially among those who have weakened immune systems due to age or underlying medical conditions. A pandemic is an epidemic that affects a very large geographic area and is often global.
During a pandemic, there are an unusually high number of hospitalizations and local health authorities will likely be overwhelmed.
Aircraft Crash
An aircraft crash creates the potential for multiple explosions and can result in an intense fire, which can lead to injuries, fatalities, and the destruction of property at and adjacent to the impact point.
In addition to the risk of aircraft damage and injury to passengers, an aircraft crash may have other effects on the Revelstoke area. A wildfire may be started by an aircraft crash, causing damage to property and resources, and possible evacuation of residents.
Dam Failure
The Revelstoke area boasts of two dams within its boundaries: the Revelstoke Dam, which is one of North America's largest and most modern, and Mica Dam which is the highest North American earth-filled dam. Both dams are classified by the Ministry of Environment as high consequence dams. This means that in the event of failure, there would be serious environmental and human impact to Revelstoke.
Motor Vehicle Crash
Motor vehicle crashes can result in a call for site support activities when they involve large numbers of people. For example, a transport truck struck a tour bus on the Trans Canada Highway near Revelstoke, in 2000, killing six people. Some motor vehicle crashes may cause ancillary emergencies, such as hazardous materials spills, that may require evacuation and sheltering efforts.
The chance of a hazardous materials spill on transportation routes is also high due to the growing volume of truck traffic.
Rail Accidents
CPR lines pass through Revelstoke transporting bulk goods. At many points, the railways travel alongside the Trans-Canada Highway, significant waterways, and the City. Aside from posing a risk to crew traveling onboard, rail accidents can pose a serious threat to the residents of nearby townships, the environment and infrastructure particularly when derailments involving dangerous goods occur.
Explosion/Gas Leaks
An explosion may be caused by the ignition of flammable gases or vapours. Common explosion sources include pipelines and utility ducts, propane storage tanks, soil-generated gases, blasting equipment, and hazardous chemicals (discussed under Hazardous Materials Accident in this section). A malfunction in any of a number of technical systems in a community could lead to an explosion. Vapour explosions are possible where flammable gases, such as propane gas, may leak and collect.
Gas leaks and explosions occur when natural gas or gasoline pipelines rupture, by accident or due to poor design or corrosion. Gas leaks can also be caused by natural hazards, such as earthquakes or landslides.
Many residents and businesses within the City rely on propane gas supplied by Teresan Gas. Gas explosions can occur when propane gas, gasoline or oil pipelines rupture. In addition the Terasen facility is protected by fencing, intrusion alarms and water monitors. Nevertheless a potential for emergency exists.
In addition, there are helicopter fuel storage tanks in the Westside Road area close to the City that may pose a potential threat. Mills usually store dangerous materials such as diesel, propane and other explosives materials on-site that could potentially cause an explosion and ultimately force the evacuation of adjacent property or require a response if municipal lands are affected.
Hazardous Materials Incident
A hazardous materials incident involves the uncontrolled release of a hazardous substance during storage or use from a fixed facility or mobile transport. Possible effects range from straightforward road closures to widespread evacuation and injury.
Potentially flammable materials are located at many gas stations and bulk fuel cardlocks, sawmills, lumber yards (glue, paint thinner, gas) and other light industry sites in the City.
In addition to these industries, various facilities within the City of Revelstoke possess hazardous materials and chemicals that can potentially threaten the well being and safety of residents if mishandled. For example, the local community hockey arena and water treatment plant handles significant amounts of ammonia and chlorine. As well, the local sewage treatment plant manages bio-hazardous waste, as well as chlorine and other chemicals used in processing.
Further, the volume of hazardous materials transported by road and rail through the City of Revelstoke is high. Fuels such as propane, diesel and gasoline are transported by road throughout the backcountry to logging and mining operations. Large volumes of hazardous materials are transported by CPR rail on a daily basis through the City of Revelstoke to the remainder of British Columbia.
Power Outage
Causes of power outages include damage to hydro poles from heavy winds, ice storms, snow storms, falling trees or other debris, vehicle impacts, landslides, and earthquakes.
As the 1998 ice storm in eastern North America demonstrated, a prolonged power outage could lead to severe conditions for local residents and businesses, especially if it occurred during the winter months when average night-time temperatures drop below freezing. Residents without winter electricity may put themselves at risk by using alternate forms of indoor heat, including propane and poorly ventilated kerosene heaters.
