A Harmonized Heat Warning and Information System for Ontario (HWIS)

Purpose

This document outlines a Harmonized Heat Warning and Information System (HWIS) for dealing with heat events. The aspects of this HWIS include:

• Governance: roles, responsibilities, and decision-making structures
• Triggers for the issuing of various heat warning to the public health units (PHUs) from a central source, and mechanisms for disseminating these warnings
• Definitions of warnings, along with suggested core activities
• Communications messaging to support the various warning levels
• Planning guidance to support PHUs and local partners in their heat response planning

This document is intended to support planning for boards of health and public health units (PHUs) in Ontario. Other levels of government and potential partners may also choose to use the guidance contained in this document.

It is recognized that there is a wide variation in local response plans. Essential activities under the HWIS are focused on notification and communication processes. The HWIS will enable public health units to increase consistency in response to heat events and to better protect residents, vulnerable community members and visitors.

The Ontario HWIS has been informed by lessons learned from the 2015 Pan/Parapan Am Games harmonized heat alert and response pilot. In addition, this guidance has been developed based on the work of the Ontario Heat Health Project Team. The Ontario Heat Health Project Team has been meeting since 2012 and represents interagency collaboration between the Ministry of Health and Long-Term Care, public health units, Public Health Ontario, Health Canada and Environment and Climate Change Canada.

Roles and responsibilities

The Ontario Public Health Standards (OPHS) establish the minimum requirements for fundamental public health programs and services to be delivered by Ontario's 34 boards of health, which include assessment and surveillance, health promotion, health protection, and disease and injury prevention. The OPHS are published by the Minister of Health and Long-Term Care, pursuant to Section 7 of the Health Protection and Promotion Act, R.S.O. 1990, c. H.7.

Under the Health Hazard Response Protocol, 2019, public health units are required to prevent and reduce the burden of illness from health hazards in the physical environment, including extreme weather and extreme temperatures.

Public health units (PHUs)

Health unit actions to mitigate heat health impacts may include alerting and response activities. The response activities that the PHU itself is directly responsible for vary because of the variance in municipal hot weather response plans. PHUs may also have varying responsibilities in working with municipalities and other community partners to ensure that other aspects of the response plans are delivered. PHUs should ensure that roles and responsibilities are clear and that planning links are well established prior to a heat event. As part of the Ontario HWIS, PHUs can expect to:

• receive the heat warnings provided by Environment and Climate Change Canada (ECCC)
• communicate information based on the heat warnings and appropriate health protective measures
• review the guidance provided regarding local partnerships and planning activities, and share with partners for their consideration in local heat response and/or emergency management plans
• conduct surveillance of local heat related health impacts
• participate in evaluation activities

Local municipalities and community partners

Municipalities and community agencies will be key partners for PHUs. Precise roles will vary. It is recommended that PHUs include appropriate local partners in the review of the response planning guidance included in this document. While local response to heat will continue to be based largely on the varied existing local heat response plans, there may be opportunities for plan improvement or enhanced coordination in the areas of:

• local partner notification processes
• public communications and support to public health heat education opportunities
• making cooling spaces and hydration accessible to the public
• working to address the needs of vulnerable populations
• responding to impacts on municipally-delivered health services such as Emergency Medical Services or Long-Term Care
• responding to impacts on critical infrastructure such as power supply
• occupational health and safety for their own workers in hot weather
• potential activation of local Emergency Operations Centres, and activation of other local emergency response plans/protocols as required

The municipalities’ roles may involve a range of various departments/divisions, ranging from recreation to public works to social services, as well as multiple community partners, from the Red Cross and utility companies to landlords, faith-based organizations, and smaller local service organizations.

Ministry of the Health (MOH)

The Ministry of Health is responsible for setting standards for public health units and monitoring PHU activity. The ministry also provides provincial emergency management leadership in the areas of human health, disease and epidemics, and health services during an emergency:

• The Office of the Chief Medical Officer Health, Public Health (OCMOHPH) to provide ongoing PHU advice in planning and evaluation activities.
• while heat response is often handled within the mechanisms of local level plans, in the event of a widespread, severe or prolonged heat emergency, or where impact on the health care system is significant (example: widespread loss of power) additional provincial emergency management coordination may be required

Environment and Climate Change Canada (ECCC)

• weather surveillance, forecasting, and issuance of:
  • public weather forecasts and early notification products
    • Ontario Vigilance Bulletin (OVB)
    • public weather forecasts
      • metnotes
    • other potential products may be available
  • public weather alerts related to heat including:
    • heat warnings
    • Special Weather Statements (SWS) related to heat

Health Canada

• providing evidence-based heat health information
• providing guidance documents and best practices

Heat warning triggers

With support from Health Canada, Public Health Ontario (PHO) conducted an epidemiological study to better understand the health impacts of extreme heat in Ontario and to support PHUs in implementing a harmonized heat warning and information system that is based on health evidence and representative of the local climate of each PHU. Health-related criteria for the new Ontario heat warnings have been developed based on the relationship between mortality, air temperature or humidex, along with other key factors such as air pollution, climate, and population characteristics. These triggers have been designated across three regions as depicted in Figure 1.

Figure 1: Map of Ontario Heat Regions

Criteria to establish heat health triggers have been developed using results from the epidemiological study conducted by PHO and considering best practices and lessons learned from other Canadian communities. Heat warning criteria have been developed based on intensity and duration of a heat event. All warning levels are based on forecasted conditions as depicted in Table 1.

Table 1: Heat warning regions and associated triggers (region, intensity and duration)

* Tmax represents maximum daily temperature. Tmin represents minimum nighttime temperature.

**A heat warning is for a two day event and an extended heat warning is for a 3+ day event.

Early Notification – Ontario Vigilance Bulletin

Before issuing a public-facing Heat Warning and within the limits of predictability, ECCC makes every effort to capture potential heat events in their significant weather outlook email to its health sector and emergency management partner distribution list once forecast guidance is certain enough to warrant elevated likelihood of a heat event. This product, called the Ontario Vigilance Bulletin (OVB) is sent as a PDF via e-mail 7 days a week by 4PM ET by the Ontario Storm Prediction Centre. The OVB will communicate expected conditions, coverage, and expected duration as is possible with available forecast guidance.

PHUs may choose to communicate this early notification to their key partners or wait for the official ECCC warning. PHUs can forward the OVB to their key partners directly or direct their key partners to sign up for the OVB. If PHUs have non-public partners involved in the provision of their heat program, they are encouraged to contact ECCC regarding the distribution of the OVB.

Early Notification – ECAlertMe

ECCC’s Warning Preparedness Meteorologists and Ontario Storm Prediction Centre operational forecasters are supporting early mobilization of public health units by notifying them in advance (up to one hour) of issuing a Heat Warning through ECAlertMe. This allows for public health units to enhance weather monitoring, intervene with those most vulnerable and to get prepared for the potential of ECCC issuing a Heat Warning. ECCC will provide an Early Notification (EN) to PHUs that threshold conditions are predicted to be exceeded. These advance EN alerts are available via the ECAlertMe system.

This prototype interface allows public partners to sign up for e-mail alerts for any alert message types and forecast regions that the Meteorological Service of Canada (MSC) forecasts. PHU and public partners involved in heat should indicate that they are part of the broader health sector to enable them to receive the one-hour advance EN that precedes a Heat Warning from ECCC. This is a self-managed subscription service, but additional instructions to support registering an account and setting up alerts are available upon request.

PHUs may sign up for an ECAlertMe account at: https://ecalertme.weather.gc.ca/home_en.php.

Warning process

When conditions are likely to meet two days or more of warning criteria, then ECCC will issue a Heat Warning. To determine when the warning should be issued, forecasters will assess the certainty of experiencing two consecutive days of weather that meets the set criteria for humidex and temperature (daytime highs and nighttime lows). If either temperature or humidex conditions are expected to be met, a Heat Warning will be issued. ECCC will use criteria which vary across the province for the three regions as identified in Figure 1.

In ideal circumstances, ECCC will issue Heat Warnings 18-24 hours in advance of heat conditions being met publicly via the WeatherCAN app and the ECCC Weather Alerts webpage. Sometimes, the forecast is inconclusive or has a high degree of variability; this may result in delayed notification or delayed declaration of a heat warning referred to as a ‘short-fuse’ Heat Warning. An EN before public issuance of the Heat Warning can still be expected.

Summary of PHU activities based on ECCC notifications:

• Early Notification – PHUs activate notifications to key partners
• Heat Warning – PHUs notify key partners and activate communications activities, example: media activities, to share information with the public about risks and health protective measures, based on ECCC’s Heat Warning
• Extended Heat Warning – (ECCC notification that heat warning is continuing beyond 2 days) – within the context of local plans, PHUs communicate the Extended Heat Warning message and work with municipal and community partners to implement response activities.

Some modification to existing heat response plans may be required, and local PHUs may need to issue additional media communications. The decision to operationalize additional response plans and/or media communications remains with local Medical Officers of Health.

The chart below identifies the key steps involved in the heat warning process. These steps are not necessarily sequential. For example, the notification may be initiated at the Heat Warning stage, or the event could be de-escalated, without an Extended Heat Warning being called.

Notification and Warning Process from ECCC to PHUs and Community Partners

• Monitoring: Environment and Climate Change Canada (ECCC) monitors weather forecast
• Early Notification: ECCC advises PHU that conditions/criteria are forecast to be met in advance of issuing a Heat Warning. Warning is issued publicly 18-24 hours in advance of the criteria being achieved.
• Heat Warning: ECCC advises PHU that conditions/criteria have been met. PHU gives a heads-up to municipalities and partners that conditions have been met and to prepare. PHU notifies media of Heat Warning as appropriate (example: share health protective messaging with public.)
• Extended Heat Warning: Continued if forecast conditions persist as advised in previous email to PHU. PHU notifies and works with municipalities and community partners within the context of local plans to implement response activities
• Notification of De-Escalation: ECCC issues public notification that heat warning is ended as conditions are no longer in effect. PHU notifies municipalities/partners and may decide on additional notifications to media as required

Extended heat warnings

ECCC’s Heat Warning that extends 3+ days would constitute an Extended Heat Warning at the local PHU level. While the ECCC terminology for a prolonged event will not change (example: Heat Warning, PHUs are strongly encouraged to use the terminology Extended Heat Warning, when communicating information about a heat event meeting the heat warning criteria that extends beyond 2 days.

While Extended Heat Warnings are based on forecast conditions, PHUs are strongly encouraged to stage the escalation from Heat Warning to an Extended Heat Warning. For example, if a 3 day heat event is forecasted, the PHU would notify partners and/or issue a heat warning on the day prior to the Heat Warning conditions being met (when ECCC issues heat warning). If on Day 2 of the heat warning, Environment and Climate Change Canada indicates the heat warning will continue into a third day, the PHU would upgrade to an Extended Heat Warning for the following day/s (and/or issue an extended heat warning). An example of the escalation process is depicted in Table 2. Extended Heat Warnings are not issued and/or disseminated by ECCC.

A PHU may consider additional local factors in the escalation to an extended heat warning, for example residents may not be acclimatized to extreme heat early in the season, power outages that may impact the ability of vulnerable populations to cool down, and surveillance of hospital visits attributable to extreme heat.

Table 2: Example of Public Health Unit action in response to heat trigger escalation

While all PHUs will notify partners and media, some PHUs may choose to use language conveying that the PHU/MOH has issued a heat warning (based on ECCC heat warning), and others may choose to simply relay Environment and Climate Change Canada’s heat warning. It is important to note, however, that these notifications and issuances be based on Environment and Climate Change Canada’s criteria for heat warnings. As noted above, PHUs may consider additional factors when escalating to an Extended Heat Warning. PHUs may need to issue additional media communications, however, the decision for how these processes will be operationalized, remains with the individual local Medical Officers of Health.

Other ECCC public facing messaging

A Special Weather Statement will be issued at the discretion of the MSC with the first forecast of a heat event in the season up until the Canada Day weekend, when conditions do not meet heat warning criteria but could pose health risks, particularly to those vulnerable to the heat who are not yet acclimatized to the warmer weather. The MSC shall use single day criteria (for maximum temperature and/or maximum humidex) for the Special Weather Statement as guidance for issuance for affected forecast regions. Ideally, the Statement will be geographically relevant for entire Heat Regions. The MSC also maintains discretion for issuing Special Weather Statements for other one day events for the season. The MSC will endeavor to provide Early Notification emails one hour in advance of the Special Weather Statement. In all cases, the heat warning will trump the issuance of a Special Weather Statement for heat.

On the ECCC WeatherCAN app, there is a newer product available on Location pages called a Metnote. Metnotes are an opportunity for forecasters to communicate potentially impactful weather or weather of note that does not meet warning criteria to the public. Metnotes may occasionally reference temperatures or speak to abnormal temperature trends.

Communications and messaging

The need for standardized heat health messaging has been identified as a key component of a harmonized HWIS. A number of PHUs and municipalities disseminate heat-health communications to residents while some regions in Ontario do not. Without a consistent approach, residents, who are exposed to messages from neighbouring jurisdictions, often struggle to understand warning terminology and triggers. Consistency is important in both the types of heat-health messaging communicated, and the terminology used in communication.

As noted in the Heat Warning Section, while PHUs are encouraged to incorporate ECCC’s “heat warning” terminology, some PHUs may choose to use language conveying that the PHU/local MOHs have issued a heat warning (based on ECCC heat warning), while others may choose to simply relay ECCC’s heat warning.

Timing for dissemination of heat-health messages may also be improved by raising pre-season and pre-event awareness across the province, thereby contributing to better heat-health knowledge and preparedness of the public before the onset of a heat event. In addition, post-event communications are often omitted from heat-health communication plans in Ontario, revealing a missed window of opportunity for building awareness as well as delivery of messages to those who are still coping with post-event stress.

Municipalities and PHUs target similar heat-vulnerable populations. If effectively coordinated, heat-health communication campaigns can be strengthened through broad dissemination. Use of consistent and standardized messaging is integral.

Health Canada's Communicating the Health Risks of Extreme Heat Events: Toolkit for Public Health and Emergency Management Officials (Toolkit), identified scientifically sound heat-health messages for public communication. PHUs should use this messaging in their heat-health communications.

Health Canada’s heat-health messages:

Message 1: Heat illnesses are preventable.

Message 2: While extreme heat can put everyone at risk from heat illnesses, health risks are greatest for:

• older adults;
• infants and young children;
• people with chronic illnesses, such as breathing difficulties, heart conditions, or psychiatric illnesses;
• people who work in the heat;
• people who exercise in the heat;
• people experiencing homelessness; and
• low-income earners.

Message 3: If you are taking medication or have a health condition, ask your doctor or pharmacist if it increases your health risk in the heat and follow their recommendations.

Message 4: Heat illnesses include heat stroke, heat exhaustion, heat fainting, heat edema (swelling of hands, feet and ankles), heat rash and heat cramps (muscle cramps). Watch for symptoms of heat illness, which include:

• dizziness or fainting;
• nausea or vomiting;
• headache;
• rapid breathing and heartbeat;
• extreme thirst; and
• decreased urination with unusually dark yellow urine.

If you experience any of these symptoms during extreme heat, immediately move to a cool place and drink liquids. Water is best.

Message 5: Heat stroke is a medical emergency! Call 911 or your local emergency number immediately if you are caring for someone, such as a neighbour, who has a high body temperature and is either unconscious, confused or has stopped sweating. While waiting for help - cool the person right away by:

• moving them to a cool place, if you can;
• applying cold water to large areas of the skin or clothing; and
• fanning the person as much as possible.

Message 6: Frequently visit neighbours, friends and older family members, especially those who are chronically ill, to make sure that they are cool and hydrated.

Message 7: Drink plenty of cool liquids, especially water, before you feel thirsty to decrease your risk of dehydration. Thirst is not a good indicator of dehydration.

Message 8: Reschedule or plan outdoor activities during cooler parts of the day.

Message 9: Wear loose-fitting, light-coloured clothing made of breathable fabric.

Message 10: Never leave people or pets in your care inside a parked vehicle or in direct sunlight.

Message 11: Take a break from the heat by spending a few hours in a cool place. It could be a tree-shaded area, swimming facility or an air-conditioned spot such as a public building, shopping mall, grocery store, place of worship or public library.

Message 12: Take cool showers or baths until you feel refreshed.

Message 13: Prepare meals that don't need to be cooked in your oven.

Message 14: Block sun out by closing awnings, curtains or blinds during the day.

Message 15: Avoid sun exposure. Shade yourself by wearing a wide-brimmed, breathable hat or using an umbrella.

Supplemental Messages

Message 16 (Heat-Health in the North): Extreme heat puts everyone at risk of heat illnesses. People living in areas with cooler climates can be more susceptible to extreme heat than those who are regularly exposed to hot environments and have had an opportunity to acclimatize to warmer temperatures. Heat illnesses include heat stroke, heat exhaustion, heat fainting, heat edema (swelling of hands, feet and ankles), heat rash and heat cramps (muscle cramps). Watch for symptoms of heat illness, which include:

• dizziness or fainting
• nausea or vomiting
• headache
• rapid breathing and heartbeat
• extreme thirst
• decreased urination with unusually dark yellow urine

If you experience any of these symptoms during extreme heat, immediately move to a cool place and drink liquids. Water is best.

Message 17 (Heat-Health and Air Quality): Reduce strenuous activity during periods of extreme heat, and plan physical activities for cooler parts of the day. Exercise in an air-conditioned place, or a cooler outdoor location such as a tree-shaded area away from high traffic to avoid high levels of air pollution. Pollution levels tend to be higher on hot days; the Air Quality Health Index can be used to determine the air quality in your neighbourhood.

Appendix 1

Planning Guidance: Community Engagement for HWIS

Public health units work with municipalities and community partners in implementing local response plans. PHUs should ensure that roles and responsibilities are clear and that planning links are well established prior to the heat season. As previously noted, precise response measures and roles in local heat response plans vary with each municipality. This section is intended to support PHUs in engaging appropriate municipal and community partners in heat planning.

Examples of municipal and community partners include (but are not limited to):

• a range of municipal departments/areas, such as:
  • emergency management
  • community and social services
  • housing/shelter
  • fire, police and paramedic services
  • other municipally-delivered health services, such as long-term care (where relevant), home support programs or Community Health Centre programs
  • recreation/parks/community centres
  • public works
  • public transit
  • transportation and community planning
  • libraries and other municipal spaces potentially being used for cooling
• large NGOs such as Red Cross or Salvation Army, particularly if municipalities have contracts in place with them for particular services (example: water provision, cooling centre support) during emergency management response
• community housing and supportive housing organizations/ corporations, retirement homes, landlords whose populations may be at higher risk, due to either exposure or susceptibility to heat
• health system partners including private long-term care homes, community health centres, health outreach services, hospitals, Community Care Access Centres and Local Health Integration Networks.
• schools and child-care settings
• recreational facilities/community centres that are not municipally run, particularly those with water (example: pools or splash pads)
• local business owners, particularly if retail spaces such as malls are being used as cooling locations

Appendix 2

Planning Guidance: HWIS Preparation and Response Activities

In addition to the triggers and core notification and communication activities already outlined, there are a number of core activities that should be considered in a local HWIS. These activities can be categorized under:

• preparedness
• response

Another way to visualize HWIS activities is depicted in the Health Canada diagram below – describing activities seasonally: Pre-Heat Season; Heat Season; Post Heat Season; and Off Season. Both concepts provide a framework for PHUs and partners to ensure that all systems are in place to effectively manage heat events.  

PHUs are encouraged to consider the following HWIS activities in their plans:

Preparedness - activities may include but are not limited to:

• identify and make links with key partners including municipal departments/divisions, community partners, and health system partners impacted by hot weather/with a role to play in response
• carry out a local risk assessment of what populations may be vulnerable due to increased exposure to heat, susceptibility to heat, or other factors limiting their ability to take individual precautions/access planned mitigations. Depending on local risk assessment, populations to focus on  may include (but are not limited to):
  • children and infants
  • older adults, particularly if frail and isolated
  • people who exercise in the heat
  • individuals with chronic illness and/or who are physically impaired, potentially including:
    • cardiovascular or respiratory systems
    • psychiatric illnesses
    • renal illnesses
    • Taking medications that affect heat sensitivity by interfering with the body's cooling functions or water/salt retention (example: antihypertensives, antidepressants, antipsychotics, anti-Parkinson's agents)
    • dependent on others for assistance with daily living or communication
  • those disadvantaged by social circumstances (example: homeless/precariously housed, low income)
  • occupational groups with exposure to heat
• consider whether offering a registration service for vulnerable populations who may require notifications or home visits during alerts is feasible - vulnerable populations registries are acknowledged to be challenging to establish and maintain, and in many cases may not be feasible - however, local opportunities may exist with partner agencies (such as the Vulnerable Persons Registry)
• identify key community partners in accessing and supporting identified vulnerable groups, including identification of those who may benefit from education (example: residential building managers of heat-vulnerable groups)
• plan re: availability of drinking water (example: install water fountains, identify portable water stations, identify water options for homeless shelters)
• identify cooling options available to the public who don’t have air-conditioning at home - assess needs including:
  • whether transportation to cooling centres is required
  • whether overnight capabilities are required
  • whether the planned cooling centre has accessibility options in place for disabled, frail, or medical-technology dependent populations
  • whether planned cooling centre has capacity to accept family pets and/or support animals
  • what cooling centres are equipped to continue operating in the event of a power outage, and whether alternate sites also need to be developed
  • whether there are financial barriers that should be addressed (example: waiving cost of entry to public pools) 
• based on assessment, equip cooling spaces as needed (example: drinking water, snacks, cots, first aid or medical support)
• cooling options may include but are not limited to:
  • air-conditioned public properties/facilities such as libraries/community centres
  • air-conditioned rooms or common spaces in residential spaces like apartment buildings
  • air-conditioned privately-owned spaces  such as malls or movie theatres
  • community parks and other shaded green space
  • community swimming pools or splash pads
  • extending opening hours or reducing fees/tickets at any of the above
• consider financial barriers to individuals cooling themselves and whether mitigations are possible (example: utility bills, cost of fans and air conditioners)
• ensure the PHU’s Continuity of Operations plans include provisions regarding operating during hot weather, including staffing contingency plans for holiday months and identification of staff who may be heat-vulnerable and need alternate deployments
• develop an evaluation plan

Public education:

• identify key community partners who can assist in accessing and supporting identified vulnerable groups, including identification of those who may benefit from targeted or specific education (example: residential building managers of heat-vulnerable groups)
• develop and deliver education and messaging to the public on how to protect themselves and their families in hot weather, including targeted communications/materials for vulnerable populations. An example of communications/materials may be found at the Health Canada website
• develop and deliver education to key response partners where required
• information should be available in different formats and should reflect the needs of your community - if possible, it may be beneficial to design a webpage with heat specific information that can be accessed by the public and has useful resources available

Media:

• utilize local media as an important tool to ensure that messaging reaches the public on how they can protect their health during a heat event.
• utilize social and other media to disseminate information about specific interventions, such as cooling centres locations or hours, or hotlines available to the public for more information on managing heat.

Response activities (may include but are not limited to):

• activate/communicate with partners to open cooling facilities and ensure locations and hours of operation are clearly communicated
• activate/communicate with partners to implement hydration solutions, such as portable water stations or distribution of drinking water to homeless shelters and in parks and ensure activities/locations are clearly communicated
• if registration options have been put in place, check on pre-registered heat-vulnerable people as agreed (example: visit or telephone call)
• with key partners, deliver services to identified heat-vulnerable groups
• Link with health care partners re: activation of hospital, CCAC and LTC Home response plan(s)
• in consultation/partnership with municipalities, modify or cancel scheduled sports and outdoor events at daycares, summer camps, etc.
• modify work-rest cycles for public workers exposed to extreme heat

Debrief – heat emergency

In the event that local emergency management plans are activated, it is recommended that PHUs undertake a “hotwash” – the immediate collection of feedback following the event – and a debrief. Debriefing provides an opportunity to evaluate efficiency, learn from the experience gained, and determine how well the process went. Major emergency responses are generally followed up by an After Action Report (AAR) to provide feedback on performance during a response. An AAR summarizes what happened, analyzes performance of the tasks identified, and reveals the demonstrated capacity to accomplish the overall goal. The AAR includes recommendations for improvements to the process based on the analysis, which can be addressed in an improvement plan.