When the weather conditions at a place differ significantly from long-term expected patterns, they can present a hazard to the people, property and infrastructure located there.
These events are often referred to as extreme weather and can vary in duration from hours to days, in the case of heavy rain and thunderstorms, to weeks, months or even years in the case of droughts.
Please see below for a description of some of the main weather hazards that can affect Otago and how they may be influenced by climate change. Please note the ORC Natural Hazards Database Portal does not currently hold mapping for drought, wildfire, snowfall, strong wind or thunderstorm weather hazards affecting the Otago region.
Earth experiences natural changes in its climate, the rate of these changes. The impacts we observe today are the result of historical emissions, and the increase in emissions in recent decades will lead to significant change in the coming years.
Our hazards database is intended to improve public access to hazard information and to help the public, local authorities, and others make informed decisions about their exposure to natural hazards.
A drought occurs when a place receives substantially less rainfall than expected over a significant period of time (from weeks to months and beyond), resulting in a shortage of available water.
This can cause a wide range of impacts to people and the environment, from soil erosion and damage to productive land, to reduction in numbers of plant and animal species and conflict over water resources.
Climate change is expected to cause more variation in the longer-term weather conditions and patterns of a place. This may influence the duration and intensity of droughts in Otago, with some areas becoming hotter and staying drier for longer.
More information is available on our climate change pages.
Wildfires are large, uncontrolled and destructive fires, that can spread quickly through both rural and urban areas. They can be triggered by natural events such as by lightning or by human activities (for example by fireworks or discarded cigarettes) and can grow from a spark to an inferno in minutes.
Wildfires can cause major damage and destruction to anything in their path. They can incinerate large areas of bushland, crops and pastures, significantly damage or destroy property and infrastructure, and present an extreme risk to life for people and animals.
During the warmer months of the year, higher temperatures and drier weather conditions are favourable for the triggering of wildfires. Strong winds can also funnel and fan wildfires, helping them advance quickly and often unpredictably.
Some areas in Otago may become hotter and drier for longer with climate change, increasing the risk for wildfires.
Please visit our Climate Change pages for information on climate change projections for Otago.
Snowfall can present a major hazard for people in Otago, particularly when deep snow builds up in densely populated coastal areas which are not regularly affected by snow. Heavy snow loads can collapse roofs and gutters and bring down power and telephone lines.
Snow can also close roads and affect transport links such as airports, rail lines and bus services. Road access across the region can be affected, particularly the alpine passes such as the Lindis and Haast, and State Highway 1 north and south of Dunedin.
Snow may fall to sea level for one to three days and form into drifts.
When snow persists for several days, frosts and widespread ice can also develop, causing dangerous conditions under foot and on our roads.
Climate change is expected to cause more variation in the longer-term weather conditions and patterns of a place. This may influence the frequency and intensity of snowfall events in Otago, with more snow falling at once and longer periods in between with none at all. This may have a considerable impact on industries that rely on regular snow fall for their operations, while the impacts of snow fall events may be more pronounced.
Please click here for more information on climate change in Otago.
Snowfall can present a major hazard for people in Otago, particularly when deep snow builds up in densely populated coastal areas which are not regularly affected by snow. Heavy snow loads can collapse roofs and gutters and bring down power and telephone lines.
Snow can also close roads and affect transport links such as airports, rail lines and bus services. Road access across the region can be affected, particularly the alpine passes such as the Lindis and Haast, and State Highway 1 north and south of Dunedin.
Snow may fall to sea level for one to three days and form into drifts.
When snow persists for several days, frosts and widespread ice can also develop, causing dangerous conditions under foot and on our roads.
Climate change is expected to cause more variation in the longer-term weather conditions and patterns of a place. This may influence the frequency and intensity of snowfall events in Otago, with more snow falling at once and longer periods in between with none at all. This may have a considerable impact on industries that rely on regular snow fall for their operations, while the impacts of snow fall events may be more pronounced.
Please click here for more information on climate change in Otago.
Heavy rain and thunderstorm events can present a significant hazard for people in Otago. Heavy rain can cause rivers and streams to overtop their banks, causing major flooding in the surrounding areas. Water can also pool in areas where drainage is poor and the capacity of the ground surface to absorb excess water is lost. This can cause major water damage to property and infrastructure, make roads impassable, and pose a threat to human life where flood waters are fast and deep.
During thunderstorms, localised, short bursts rainfall can reach intensities of 25 mm and hour or more, resulting in very large amounts of rainfall over a short space of time. This can trigger rockfall and landslides alongside roads, and flash flood type hazards in the areas surrounding alluvial fans at the foot of steep stream catchments.
Thunderstorms also produce lightening which can pose a significant threat to people, property and infrastructure when it strikes the ground. Cloud to ground lightening can strike buildings, trees, people and animals, as well as trigger wildfires and cause major damage to electrical infrastructure. Thunderstorms often develop very quickly and are difficult to predict.
Climate change is expected to cause more variation in the longer-term weather conditions and patterns of a place. This may influence the frequency and intensity of heavy rain, thunderstorm and large-scale weather system events in Otago, with potentially more frequent and heavier rainfall, more destructive thunderstorms and more favourable conditions for ex-tropical cyclone systems to make their way south into Otago.
Please click here to visit the Otago Civil Defence and Emergency Management website for tips on how you can get ready for major storm events in Otago.
Emergency Management Otago (Civil Defence Otago) helps keep people better prepared for emergencies and well-informed during emergencies.
Earth experiences natural changes in its climate, the rate of these changes. The impacts we observe today are the result of historical emissions, and the increase in emissions in recent decades will lead to significant change in the coming years.
Our hazards database is intended to improve public access to hazard information and to help the public, local authorities, and others make informed decisions about their exposure to natural hazards.