Weather Alerts and Warnings

Heat Warnings

Extreme heat events can put the public at risk of heat-related illnesses. Four environmental factors work together to make it hot enough to put health at risk. This includes high temperature, high relative humidity (moisture in the air), radiant heat (from the sun) and low wind speed (lack of air movement).  Additionally, an individual’s health can depend on their sensitivity, acclimatization and their own as well as their community’s adaptability to extreme heat.

The Haldimand-Norfolk Health Unit’s Medical Officer of Health issues a Heat Warning or an Extended Heat Warning upon notification from Environment Canada and Climate Change Canada that certain extreme heat thresholds have been met. Details for each warning and its triggers can be found below.

Heat Warning	A Heat Warning will be issued when:   two consecutive days are forecasted to have a daytime high temperature of 31C or higher and a nighttime temperature of 20C or higher; or two consecutive days are forecasted to have a humidex of 40C or higher.
Extended Heat Warning	An Extended Heat Warning will be issued when:   three or more consecutive days are forecasted to have a daytime high temperature of 31C or higher and a nighttime temperature of 20C or higher; or three or more consecutive days are forecasted to have a humidex of 40C or higher.

Heat Affects Everybody.

Heat illnesses are preventable and knowing the risks and how to protect yourself and your family will keep you safe over the summer. Much like a fever, extreme heat stresses your body’s ability to maintain its normal temperature and can lead to a heat stroke. When out in the heat, 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. A list of heat-related illnesses and their symptoms can be found below from the Government of Canada website:

	Health Effects	Causes and Signs
	Heat Stroke	The most serious type of heat illness is a result of body heat overload. Signs of heat stroke may include a core body temperature of more than 40C/104F, complete or partial loss of consciousness and/or reduced mental ability. Sweating is not a good indicator, as there are two types of heat stroke: Classic – accompanied by little or no sweating, usually occurring in children, those who are chronically ill and older adults. Exertional – accompanied by an increase in body temperature because of strenuous exercise or occupational exposure in combination with environmental heat, and where sweating is usually present.
	Heat Exhaustion	Caused by excessive loss of water and salt. Symptoms may include heavy sweating, weakness, dizziness, nausea, headache, diarrhea and muscle cramps.
	Heat Fainting	Caused by the loss of body fluids through sweating and by lowered blood pressure due to the pooling of blood in the legs. Symptoms include temporary dizziness and fainting resulting from an insufficient flow of blood to the brain while a person is standing.
	Heat Cramps	Caused by a salt imbalance resulting from a failure to replace salt lost through excessive sweating. Symptoms are sharp muscle pains.
	Heat Rash	A result of inflammation of clogged sweat glands and accompanied by tiny red spots on the skin, which may give a prickling sensation.
	Heat Edema	Heat-induced swelling is frequently noticeable in the ankles, feet and hands, and is most often seen in people who are not regularly exposed to heat

Who is Most at Risk?

Where Can I Go To Cool Down?

During Heat Warnings or Extreme Heat Warnings, participating service providers in Haldimand and Norfolk counties will provide designated sites and recreational activities to help you cool down. A list of locations and services can be found below.

What Else Can I Do to Prevent Heat-Related Illnesses?

The HNHU recommends taking the following actions to stay cool and prevent heat-related illness:

• Drink plenty of cool liquids, especially water, before feeling thirsty.
• Wear loose-fitting, light-coloured clothing made of breathable fabric.
• Take cool showers or baths until you feel refreshed.
• Take a break from the heat by spending a few hours in a cool place.
• Block sun out by closing awnings, curtains or blinds during the day.
• If you must be outdoors, avoid sun exposure by staying in the shade; wear a wide-brimmed, breathable hat or use an umbrella.
• 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.
• Plan outdoor activities during cooler parts of the day (in the early morning or evening).
• Never leave people or pets in your care inside a parked vehicle or in direct sunlight.
• Frequently visit neighbours, friends and older family members, especially those who are chronically ill, to make sure that they are cool and hydrated.

Other Weather Warnings

Other local weather warnings (such as air quality or thunderstorms) can be found on the Environment and Climate Change Canada.