2021 Heat Dome Report

  9 June 2022

On June 7th, the BC Coroners Service released its review of the heat-related deaths that occurred across the province in late June and early July 2021. It found 619 deaths were attributable to the heat dome. Most of the deceased were older adults with compromised health due to multiple chronic diseases and who lived alone. Each one of these lives mattered and ended prematurely because of climate change and our built environment.

Click here to read the full report.

Major Findings

  • 98% of deaths occurred indoors;
  • There was a lag between the heat alerts issued by Environment and Climate Change Canada (ECCC) and public agencies and the public response;
  • Heat-related deaths were higher among persons on specific chronic disease registries (schizophrenia, substance use disorder, epilepsy, chronic obstructive pulmonary disease, depression, asthma, mood and anxiety disorders, and diabetes) compared to the B.C. population;
  • More than 60% of decedents had seen a medical professional within the month prior to their death;
  • 67% (415) of decedents were 70 years of age or older;
  • More than half of all decedents (56%) lived alone;
  • More decedents lived in socially or materially deprived neighbourhoods than the general population;
  • Most decedents were in homes without adequate cooling systems such as air conditioners or fans;
  • 74% (457) of deaths occurred in Fraser and Vancouver Coastal Health Authorities; Fraser North, Fraser East, and Vancouver had the highest rates of deaths by Health Services Delivery Area (HSDA);
  • 911 calls doubled during the peak of the heat dome;
  • Paramedics attended 54% (332) of deaths with a median time of 10 minutes and 25 seconds;
    • In 50 instances, paramedics took 30 minutes or longer from time of call to scene attendance; and
    • In 17 instances, 911 callers were placed on hold for an extended period of time; and
    • In 6 instances, callers were told that there was no ambulance available at the time of call.


There are three areas of recommendations:

  1. A coordinated provincial heat alert response system
  2. Ensuring vulnerable populations are identified and supported during extreme heat events
  3. Implementing prevention and longer-term risk mitigation strategies

The second two areas are of particular interest to housing co-ops.

Ensuring vulnerable populations are identified and supported during extreme heat events

From page 32 of the report:

As identified by the BCCS investigative findings, the effects of the 2021 extreme heat event were not felt equally amongst the population. The elderly, those with chronic health conditions and materially and socially disadvantaged people were disproportionately impacted. Most of the deceased had recent contact with medical professionals prior to their deaths. Mobility or cognitive issues, poverty and discrimination, may prevent some people from accessing cooling areas during an extreme heat event and they will require services coming to them rather than be expected to access services outside of their living area.

To ensure the needs of vulnerable populations are adequately addressed, policy, planning, service development and implementation must all be considered through an equity lens.

Implementing prevention and longer-term risk mitigation strategies

From page 33 of the report:

Due to climate change, extreme weather events are likely to occur more frequently in the future. The number of people vulnerable to an extreme heat event is expected to grow as census predictions show a steadily rising elderly population and an increasing share of one person households.

A number of heat mitigation actions have been considered, and some have been implemented, but current efforts have been insufficient and this work needs to prioritized and accelerated by all levels of government and the private sector.

Focusing on prevention opportunities, adaptation strategies and longer-term risk mitigation initiatives is necessary if future mass casualty incidents due to natural disaster extreme heat events are to be avoided. In addition to personal risk mitigation, policy and planning related to the built environment and demographic changes are key.

Other Notable Comments

From page 22:

  • A heat dome occurs when an area of high pressure stays over the same area for days or even weeks, trapping very warm air underneath – rather like a lid on a pot. The definition of an extreme heat event varies based on many factors, including geographic location and weather conditions such as temperature, humidity, and cloud cover as well as the duration of the event. The temperature is much hotter than average for a particular time and place.
  • The Intergovernmental Panel on Climate Change (IPCC) concluded that the climate will continue to warm despite efforts to reduce global emissions, which will result in more frequent heat events (IPCC, 2021).
  • The human body has a core body temperature of approximately 36.6 degrees Celsius. When the body is unable to maintain this core temperature due to excessive external heat, various life threatening conditions can occur; including dehydration, heat rashes, cramps, heat exhaustion and, most serious, heat stroke. Health problems become more pronounced during a heat event for people who are unable to avoid the heat. The mechanisms and rates of heat gain and loss are impacted by many factors including age, cardiovascular fitness, chronic conditions, medications, clothing, and humidity.
  • High indoor temperature was the primary cause of injury and death during the extreme heat event. During this time, hot air became trapped indoors and continued to rise over time. Although outdoor temperatures decreased overnight, residences did not cool off, exposing people to harmful high temperatures for extended periods of time. The BC Centre for Disease Control (BCCDC) identified that people were most in danger when indoor temperatures remained above 26 degrees throughout the heat event.
  • The province’s response to COVID-19 likely further exacerbated the impact of the extreme heat event, as people may have been reluctant to congregate in public areas and as a result may have avoided cooling centres. Additionally, deployment of staff to public areas was also problematic at times with concerns about COVID-19 exposure.

Vulnerable Populations

From page 14:

  • More than 80% of decedents were on three or more chronic disease registries (see Appendix 2, Table 1).
  • Many chronic conditions impact mobility and cognition. Reduced mobility and cognitive decline may potentially impact a person’s ability to understand or to respond to extreme heat, or to self-rescue by hydrating, attending a cooling centre, or finding other relief.
    • More than two-thirds (69%) of decedents were identified as having chronic illnesses that potentially could impact mobility, including conditions such as heart failure, arthritis or Parkinson’s disease.
    • Just under two-thirds (64%) of decedents were identified with chronic illnesses that potentially could impact cognition, including mood and anxiety disorders, dementia, or schizophrenia.

From page 26:

  • Not all people experienced the same degree of heat health risks during the extreme heat event. The elderly, persons with chronic health conditions, persons living alone, those with no access to cooling, and those in particular geographic areas were more impacted by the heat.
  • Wider public awareness about heat, and targeting community training on how to recognize heat concerns is needed.
  • One of the challenges is identifying who is most vulnerable and how to adequately meet their needs during an extreme heat event.
From page 35 of the report

Things to Remember

Health Conditions
Chronic conditions, including cardiovascular disease, hypertension, lung disease and diabetes interfere with the body’s thermoregulation process increasing susceptibility to extreme heat. Some conditions including schizophrenia can affect a person’s ability to recognize overheating and to take protective action (Ebi et al., 2021).

City centers may be hotter than surrounding rural areas because of their design and construction, including: pavement and asphalt roads and walkways which absorb heat, multi-storied glass buildings which reflect sunlight and block wind, and the absence of tree canopy and other green space to provide protective cooling. (Wang et al., 2016)

Urban tree canopy reduces surface temperatures by as much as 12°C (Schwaab et al, 2021). The urban heat island effect increases heat related mortality and morbity (Santamouris, 2020).

Within urban areas, landscape and building design can result in significant temperature differences between neighborhoods (Hong et al. 2019).

Indoor temperatures are strongly influenced by the building design, construction, cardinal orientation, and size. Indoor air temperature is generally higher when the buildings have greater solar radiation indoors, southward facing, poor insulation, dark materials, low ventilation. Upper floors can be hotter because of cumulative heat transfer from lower floors upwards and downwards through the roof. (Kenny et al., 2018).

  • Two of the most impactful interventions during a heat event deal with:
    1. Ensuring people have a way of staying cool either inside their residence or elsewhere (i.e. a cooling centre, air conditioned lobby, etc.); and
    2. Conducting heat-informed checks on older adults, persons with health conditions, those living alone and those with mobility issues to consult them on their on their well-being and support needs

Co-op Resources

CHF BC has compiled several suggestions and resources to help housing co-ops support your members during heat events.

Our partners at BCNPHA also hosted a webinar that featured health officials and housing providers on how you can prepare for and help protect your members from the dangers of extreme heat and wildfire smoke this summer—and beyond.