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Extreme Heat

To access weather information and alerts for the Interior region, please visit the
Environment Canada website or download the WeatherCAN app or Alertable.

Extreme heat overview

Extreme heat events (also known as heat waves) involve high temperatures and may be combined with high humidity. During extreme heat events, individuals are at higher risk of experiencing heat-related illness. As we experienced in 2021, heat can have devastating impacts. The BC Coroners Service directly attributed 619 deaths to the 2021 extreme heat events.

Episodes like this are projected to become hotter, longer, and more frequent as BC’s climate changes. Interventions that are practical and feasible at the personal, community, governmental, and societal levels can increase community resiliency and save lives.

Heat and health

Exposure to hotter than average conditions can lead to increases in body temperature, which may cause a number of heat-related illnesses.

The impact of an extreme heat event varies from person to person based on genetics, age, and one’s ability to adapt. Heat can affect everyone's health but some people are more exposed to, and/or more physiologically/socio-economically susceptible to severe heat-related illness and death.

Those at higher risk

Those at higher risk include:

Age:

Seniors ages 65 years or older
Infants and young children

Working Conditions:

People who work outdoors
People wearing personal protective equipment (PPE) in places not temperature controlled
People who perform manual labour

Health Status:

People with chronic poor health, heart problems, or breathing difficulties or diabetes
People on certain medications
People who are pregnant
People with mental illness such as schizophrenia, depression, or anxiety
People with substance use disorders
People with limited mobility

Living Conditions:

People who live alone or are socially isolated, homeless, or unsheltered
People with low income
People living in homes with poor temperature control
People living in areas without access to green space

Mental Health and Substance Use:

Learn more about the impacts of extreme heat

Visit HealthLink BC's Heat-related Illness webpage

Heat health tips

HealthLink BC

Health Canada

Keep Children Cool

Government of BC

Extreme Heat Social Media Package

Periods of heat are often associated with wildfire smoke events in our communities. For more information on air quality, please refer to our Air Quality page.

Preparing and responding to extreme heat

Preparing for extreme heat

There are a number of steps you can take to prepare for extreme heat. For example:

Your Home

Identify a cooler space in your home to sleep at night.
Find an air-conditioned place to cool off on very hot days (e.g., stay with family and friends, visit a museum, movie theatre, library, or shopping mall).
Check that you have a working fan/air conditioner (if you have one).
Practise opening doors and windows to move cool air in at night and shutting your windows to keep the sun out during the day.
Get a digital room thermometer to check the temperature of your home so you know when it is getting too hot.

Your Friends and Family

Think of people who might be more susceptible to heat and develop a buddy system – check in with your hot weather buddy often, especially in the evenings when indoor temperatures are highest, and in the morning to see how they managed throughout the night.
If your home is cooler, invite those who are at highest risk to stay with you.

Your Health

Talk to your doctor or pharmacist if you take regular meditations to understand if it increases your health risk in the heat.
Understand the signs and symptoms of heat-related illness so you can identify them right away. Take immediate action to cool down and call for help if needed.

You can print this two-sided post card, Be prepared for heat this summer (PDF), and post it in your home to help remind you of these steps.

During a heat event

Keep your home cool by:

Opening windows when the outdoor temperature goes down below the indoor temperature at night
Shut windows and close curtains/blinds to keep cooler air in and the sun out
Avoid making meals using the oven
Important: If you are experiencing extreme heat during an air quality advisory, prioritize cooling down. Heat is typically more dangerous than short-term exposure to poor air quality.

Keep your body cool by:

Wearing a damp towel or shirt
Taking a cool bath or shower
Putting an ice tray in front of a fan
Using a personal mister or spray bottle
Drinking lots or water
Lowering your activity level and avoiding intense activities
Important: While fans can help you feel more comfortable, they do not work to lower body temperature for older people at temperatures over 35C.

Do your best to take care of high-risk individuals by:

Visiting them to check their indoor temperature
Encouraging them to take cool baths and sleep in their coolest room
Invite them to your house if you have air conditioning
Never leave children, dependent adults or pets alone in a parked car. Leaving windows open will not help.

Symptoms

Severe heat illness and heat stroke are medical emergencies. Call 9-1-1 if you are caring for someone with signs or symptoms of severe heat-related illness. Symptoms of severe heat-related illness include:

Nausea and/or vomiting
Faint or loss of consciousness
Confusion or disorientation
Difficulty speaking
Movement and coordination problems
Lethargy
Not sweating
Hot, flushed or very pale skin
Not urinating or very little urinating
Rapid breathing and faint, rapid heart rate
Body temperature >39°C (102°F)

While waiting for help to arrive, you can help cool the person by:

Moving them to a cool place, if possible
Remove excess clothing
Apply cold water, wet towels or ice packs around the body, especially the neck, armpits, and groin

Symptoms of mild to moderate heat-related illness include:

Headache
Nausea
Weakness
Irritability
Light-headed or dizziness
Disorientation
Thirst or dry mouth
Difficulty swallowing
Fatigue, malaise
Heat rash, heat edema or heat cramps
Decreased urine output
Increased heart rate
Skins feels very warm and sweaty
Body temperature >38°C (100°F)

Mild to moderate heat-related illness can quickly become severe. Contact a health-care provider or HealthLinkBC at 8-1-1 if you are unsure. If symptoms worsen, call 9-1-1.

Learn more about the signs or heat-related illness

Heat preparation & planning resources

BC Centre for Disease Control

PreparedBC

Extreme Heat Preparedness Guide

WorkSafe BC

Heat Stress in the Workplace

Interior Health

National Collaborating Centre for Environmental Health

Health checks during extreme heat events | National Collaborating Centre for Environmental Health | NCCEH - CCSNE

BC Provincial Heat Alert Response System (HARS)

To provide consistency and guidance for community response to heat, heat alert response systems are designed to:

Warn the public about heat risk through an organized and defined communication system
Help individuals and communities prepare and protect themselves, before and after an extreme heat event
Alert decision-makers to take preventative actions to protect public health
Increase community resilience to extreme heat and develop effective actions to reduce heat-health risks, especially to those who are most susceptible.

This year, a BC HARS has been developed by the BC HEAT Committee, which is led by members of the BC Centre for Disease Control (BCCDC), the BC Ministry of Health, and Health Emergency Management BC (HEMBC). This 2-tiered response system leverages existing heat criteria used by Environment and Climate Change Canada (ECCC) as well as regional communication structures from Emergency Management BC (EMBC) to support coordination calls with partners.

BC HARS criteria

Alert Level	Heat Warning	Extreme Heat Emergency
Public Health Risk	Moderate (5% increase in mortality)	Very high (20% or more increase in mortality)
Descriptor	Very hot	Dangerously hot
Criteria within Interior Health Region (listed as daytime temperature- nighttime temperature –daytime temperature)	Southeast Interior: 35 °C -18 °C -35 °C Northeast Interior: 29 °C - 14 °C - 29 °C includes North Thompson, 100 Mile House and part of Cariboo Chilcotin	Heat warning criteria have been met and forecast indicates that daily highs will substantively increase day-over-day for 3 or more consecutive days
Historic Frequency	1-3 per summer	1-2 per decade

BC HARS triggers and activation process

When temperatures reach the specified regional criteria triggers for a heat warning or an extreme heat event, the ECCC will issue a special weather statement. Heat warnings will be issued on the ECCC weather alerts webpage and on the WeatherCAN app. Extreme heat emergencies will be alerted through a Broadcast Intrusive Alert via EMBC Alert Ready.

BC HARS preparedness and actions

The issuing of a Heat Warning or Extreme Heat Emergency should activate a series of actions by different ministries, levels of government, public health organizations, and professionals, as well as the general public. Tables containing key messages and recommended actions are provided in the BC HARS for consideration when preparing for and responding to the different heat alerts. They are meant as a tool to initiate heat planning, or to complement and support more robust heat plans, ultimately building more resilient communities for the years ahead.

Examples include:

Leading into a heat wave or extreme heat event: This may include education about the risks of extreme heat, precautions to take, signs of heat illness to watch for, and recommended times to stay indoors/outdoors.
At the peak of a heat wave or extreme heat event: This may include recommendations for outdoor workers, Sunscreen SPF and hydration recommendations, ideas about where to seek air conditioning/shade, suggestions to check in on family members or vulnerable individuals, and what to do if you suspect you or someone you know has heat stroke.
Leading out of a heat wave or extreme heat event: This may include recommendations on easing back into physical activity, continuing to monitor for heat illness or dehydration, and continuing to use caution as indoor temperatures may remain high (despite a drop in outdoor temperatures).