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Learn how to prepare for and what to do during a thunderstorm in New Zealand to minimise risk to you and your loved ones.
Every household should create and practice a Household Emergency Plan. It's also important to have emergency survival items and a getaway kit. As well as this, every household should plan and practice what to do if a thunderstorm happens.
What to do
- Learn about thunderstorm risks.
- Get your household ready.
- Keep an ‘in case of thunderstorm’ to-do list.
More information on how to prepare for and what to do if you get stuck in a thunderstorm:Thunderstorms - Civil Defence (PDF)
More about thunderstorms
Thunderstorms are short-lived, existing for no more than one or two hours, and dangerous. With each thunderstorm comes lightning (thunder is just the sound of lightning) along with very heavy rain and sometimes hail, strong straight-line winds and tornadoes.
Rain associated with a single thunderstorm falls over a small area. While no single thunderstorm will produce widespread flooding, the suddenness and sheer intensity of the rainfall over a localised area can be hazardous. In urban areas, the result is often an overloading of the stormwater system and surface flooding. The same amount of rainfall in the catchment of a small stream can rapidly transform it into a raging torrent.
In New Zealand, the hail associated with thunderstorms is generally small by international standards. Nevertheless, it can be large enough to devastate crops, damage roofs and break glass. When it falls in large quantities, small hail can be centimetres deep and a significant driving hazard.
Thunderstorms commonly have strong winds associated with them. Irrespective of whether these are straight-line or tornadic (rotating), these winds are sudden, violent and short-lived, and can cause large amounts of damage. As with the rain or hail from a single thunderstorm, the strong winds are confined to a small area. If the thunderstorm is moving, the extent of rain, hail or strong winds is typically no more than a few hundred metres wide and a few kilometres long.