Hazard Identification Report 2019 Section B: Environmental Hazards Hazard Identification and Risk Assessment Program Office of the Fire Marshal and Emergency Management Introduction The Hazard Report contains information profiles for hazards, including a high-level overview of possible consequences. It is divided into 10 parts; an introduction and 9 sub-sections labelled A-I as follows: A. Agriculture and Food F. Public Safety B. Environmental G. Structural C. Extraterrestrial H. Supply and Distribution D. Hazardous Materials I. Transportation E. Health Contents Environmental Hazards: Hazards related to the interaction of environmental forces with human systems and environments Avalanche ....................................................................................................................... 3 Drought or Low Water ..................................................................................................... 7 Earthquake .................................................................................................................... 13 Erosion .......................................................................................................................... 19 Extreme Cold ................................................................................................................ 24 Extreme Heat ................................................................................................................ 30 Flood ............................................................................................................................. 36 Fog ................................................................................................................................ 44 High Wind ...................................................................................................................... 48 Hurricane ....................................................................................................................... 53 Landslide ....................................................................................................................... 59 Land Subsidence .......................................................................................................... 64 Lightning ........................................................................................................................ 69 Storm Surge .................................................................................................................. 74 Thunderstorm ................................................................................................................ 78 Tornado ......................................................................................................................... 83 Wildland Fire (Forest Fire, Wildfire) ............................................................................... 90 Winter Weather ............................................................................................................. 96 Hazard Identification Report 2019 – Section B Page 2 of 103 Avalanche Photo Credit: Gaijin Ninja. "Alpine Chairlift View." Feb 26,2012. Online image. Accessed Feb 21 2019. <https://commons.wikimedia.org/wiki/File:AlpineChairliftView.JPG> Avalanche Go to next hazard: Drought or Low Water Definition A snow avalanche ensues when a pent up snow mass loses its hold and is discharged from a slope. Description Snow can fracture when the strength of the bonds that hold it together are overcome by stress that overloads the bonds. If enough bonds fracture at once, an avalanche occurs. The sources of stress that can overload a snowpack and cause fracture are called triggers. Natural triggers occur independently of human activity. Some common natural triggers are: • Loading from new snow, wind driven snow or rain. • Temperature changes and thawing caused by warm air and solar radiation. Even if the right snowpack conditions and triggers are available, avalanches will only occur on terrain with certain features and characteristics. Avalanches are most likely to occur on slopes between 30-45 degrees, and in areas where wind causes snow to accumulate, and where sun exposure has resulted in weak snow due to rapid warming and melting. The three main types of avalanche are: • Sluffs/Sloughs: Small slides of dry powdery snow that move as a formless mass • Slab: Slabs of snow break loose from a mountainside and shatter like broken glass as they race downhill. These moving masses can reach speeds of 80 miles (130 kilometers) per hour within about five seconds. • Wet: Low velocity suspension of snow and water, with the flow confined to the track surface. Can be initiated from either loose snow releases, or slab releases, and only occur in snow packs that are water saturated Every modern ski resort will issue notices (bulletins) indicating the level of Avalanche Risk for each day. These risk levels range from Low to Very high (extreme). Spatial Scale, Timing and Warning period Spatial Scale: The spatial scale of avalanche in Ontario would be small, and usually away from settlements. Hazard Identification Report 2019 – Section B Page 4 of 103 Timing: Avalanche could occur during the winter and into the spring, and are most common in the 24 hours following heavy snowfall. Warning Period: The warning period would vary from 24 hours to seasonal in scale. Potential Impact A strong Avalanche may result in: • The need for debris management • Reports of missing individuals. The need for search and rescue, family reunification operations • Multi-modal transport disruptions, the need for detours or re-routing. May strain transportation management resources and cause transportation delays. • The need for damage assessment. • The need for evacuation or shelter in place. • Property and structural damage, the need for repair. Possible impact on Critical Infrastructure. • The need for site or area access restrictions. Secondary Hazards Potential secondary hazards may include: • Building or Structure Failure • Erosion • Rail, Light Rail, Subway • Road and Highway Past Incidents There have been two incidents of avalanche recorded for Ontario in the Canadian Disaster Database: • Scarborough, 1972: An avalanche in highland creek killed 2 people. • Chelmsford, 1978: An avalanche killed 1 individual that was hiking in Chelmsford area. Both avalanches were small and isolated. Provincial Risk Statement Avalanches are exceedingly rare in Ontario. While snow is common, the terrain is generally not steep enough to create significant avalanche risk. Educating the general public about avalanche risk, as well as sign-posting and cordoning off areas at risk for such hazards are the most utilized and effective means of Hazard Identification Report 2019 – Section B Page 5 of 103 prevention. There are also safety courses and other further education opportunities available for those spending a lot of time in the backcountry. Given that the risk of avalanche is so low in Ontario, further mitigation measures are seldom needed. Human Impacts Avalanche rarely results in fatalities or injuries. Social Impacts Avalanche would not lead to impacts on community support mechanisms. Property Damage Property can be vulnerable to avalanche, though the occurrence is extremely unlikely in Ontario. Critical Infrastructure Disruptions Critical Infrastructure can be vulnerable to avalanche, though the occurrence is extremely unlikely in Ontario. Environmental Damage Avalanche would not result in environmental damage, except when it damages forests and trees. Economic Avalanche could result in very limited economic impacts, though this is unlikely in Ontario. Hazard Identification Report 2019 – Section B Page 6 of 103 Drought or Low Water Photo Credit: Taylor, Robert. "Healey Falls Low Water." Jul 16,2011. Online image. Accessed Feb 21 2019. <https://commons.wikimedia. org/wiki/File:Healey_Falls_Low_Water,_Trent_Hills,_Ontario_4949_(59 44120938).jpg> Drought or Low Water EnvironmentalGo to Previous Hazard: Avalanche Go to next hazard: Earthquake Definition Drought (also referred to as a period of low water) is an extended period, with one or more of the following: 1 • Three months or greater with below average precipitation which may be combined with high rates of evaporation. • Conditions in which the water levels in streams are at the minimum required for the survival of aquatic life. Water must be rationed only for high priority uses since many wells are becoming dry. • Conditions that have socioeconomic impacts that are felt over a much larger area than the individual properties that the drought/low water conditions have been reported at. Description Drought conditions are naturally occurring phenomenon that can also be triggered or exacerbated by human activities, such as the altering of ecosystems. They are characterized by decrease in the normal amount of precipitation that the area receives. High air temperatures leading to higher rates of evaporation may increase the severity of the drought. The amount and type of vegetation in the affected area may also contribute to the severity through evapotranspiration losses. Natural factors that influence the levels of Lake Ontario include inflow from Lake Erie and weather patterns (precipitation, wind, and temperatures). Of particular concern are lack of precipitation and warm weather, which have the greatest effect on water levels, along with reduced levels of ice during the winter, which increases evaporation. Changes to weather and climate patterns could therefore