A cold spell or cold snap can be defined as a rapid decrease in the temperature within a 24 hour period requiring substantially increased protection to agriculture, industry, commerce and social activities in the community.
The precise criterion is determined by the rate of temperature decrease as well as the minimum temperature reached. Cold spells can cause injury and possibly even death to exposed people (especially the homeless people on the streets), pets, livestock and wildlife.
Exposure to low temperatures causes the body to demand a higher caloric intake in order to maintain the required body temperature. In extreme cases, where cold spells are accompanied by heavy and persistent snow (in the mountains or higher altitudes), grazing animals may be unable to find food and die of starvation or hypothermia. In order to reduce the chances of such an event, farmers purchase foodstuff for their animals, which can also be a financial burden.
In Mediterranean-type climates, such as in Cape Town, the temperature rarely reaches 0°C. However, the higher altitude parts of the municipal area may have periods of temperature below freezing. Water expands at 4°C or below and may ice-up, and if these low temperatures are maintained, one of the hazards associated with such events are pipes (including indoor plumbing) rupturing, causing damage to property. Some metals also become brittle at low temperatures. Good insulation and even heating of your house will assist in your comfort during a cold spell. Any open flames for heating must be treated with extreme caution so that a structural fire is avoided.
By drafting your own Family Emergency Plan and identifying all your risks, including those hazards affecting your own environment, you can make a positive contribution to preparedness.