Northland Civil Defence Emergency Management Plan, 2010

Hazard and risk analyses and the review of existing control mechanisms are ongoing activities carried out by andshared among CDEM stakeholder agencies. These are further discussed within the Reduction Section of this plan.2.2.2 HAZARDS EXCLUDED FROM DETAILED ANALYSISSome hazards have not been assessed in detail but are summarised below. In general, these hazards wereexcluded from detailed analysis because they are events in which the CDEM Group is unlikely to play an active orprimary role. The hazards include:a) Urban fire can cause significant damage to commercial, industrial and retail buildings and can occur at anytime,anywhere in Northland. Fire to homes is more prevalent in some of the isolated rural areas where lack ofelectricity can mean a reliance on candles and lamps for lighting, and in lower socio-economic areas where smokealarms are either not maintained or installed.b) Large Space debris (asteroid, meteor, bolide etc) entering the earth’s atmosphere and impacting in the sea oron land is a possibility however significant events have an extremely low probability and are most likely to occur inthe ocean, potentially causing devastating tsunami waves. A significant space debris incident is considered beyondthe scope of a CDEM Group response.c) Mine subsidence: Sub-bituminous coal has been mined in several places in Northland including Kamo, Kiripaka,Hikurangi Kawakawa and at the Avoca minefields northeast of Dargaville. At each of these locations there is a riskof subsurface subsidence due to the underground mining of coal seams, however the impact is considered to bevery localised and unlikely to be in a CDEM Group role. Hazard zones and development controls are in place inKamo and Hikurangi, but other mines may need further evaluation.d) Coastal erosion is the retreat of the shoreline caused by water, waves, currents and wind. It is a naturalprocess but it can be exacerbated by human activities such as sand extraction, vegetation removal andconstruction of coastal structures. Coastal erosion occurs predominantly at sandy beaches and along weak coastalcliffs such as those located at One Tree Point. Most erosion occurs in large increments during storms when heavyswells and /or storm surges buffet the coast. During intervening calm periods a beach will generally rebuild itself.However much of Northlands coast has been modified through coastal development and some many areas areexperiencing problems with coastal erosion.e) Tornados: Tornados have been experienced at Kaitaia and Whatatiri in recent times. The tornado at Whatatiricaused mature avocado trees on a horticulture block to be knocked over along with wind damage to native trees.In Kaitaia the tornado caused damage to the hospital and homes. Around 20-30 tornadoes are observed in NZeach year, most lasting less than 15 minutes and typically small and short-lived.f) Land instability: Northland is susceptible to shallow soil slides involving the movement of the upper soil layer,often including vegetation, and deep seated creeping earthflows which occur in the saturated clay-rich areas. Onvery steep slopes the rock and soil may simply fall and accumulate on the bottom of the slope as debris. Howeverthe consequences of landslides are generally localised in scale and only widespread when associated with a storm,therefore landslip risks have been dealt with in that section.2.2.3 CLIMATE CHANGEClimate Change has not been considered as a separate hazard in this Plan, but as a factor that impacts on thefrequency and intensity of many of the other hazards. It may introduce long-term shifts in climate patterns suchas more intense rainfall and associated flooding, more frequent and intense droughts in eastern areas, moredamaging winds and increased wildfire risk especially in eastern areas, sea level rise and a change in wavepatterns.The extent to which hazards may be impacted by climate change are discussed in Appendix B. The impact ofclimate change also gets factored into the hazard prioritisation process through the application of the ‘growth’factor Refer Section 2.3.1.Northland Civil Defence Emergency Management Plan, 2010-2015 Page 24