Although Hawke's Bay doesn't have any volcanoes, the area has been affected by over 20,000 years of volcanic activity, mainly in the form of ash falls.
Mount Ruapehu (1995)
Massive eruptions can cause a volcano to collapse in on itself and form a caldera. This is what happened at Taupo. The lake is a caldera that filled with water after one of the largest volcanic explosions in human history about 1800 years ago.
With the nearest volcano about 100 km away, Hawke's Bay has been spared the worst effects of an eruption. However, because a westerly is a prevailing wind in the North Island, Hawke's Bay is vulnerable to volcanic ash falls and their associated hazards when eruptions occur in the Taupo and Central Plateau regions.
Hawke's Bay peat bogs, swamps and road cuttings record a complex sequence of ash layers from Taupo, Okataina (the area between Rotorua and Kawerau), Ruapehu and Taranaki volcanoes that date back over 20,000 years. Scientific research has determined that eruptions from the Okataina and Taupo volcanic fields could produce sufficient volcanic ash to significantly impact on Hawke's Bay. Large eruptions from Ruapehu, Tongariro, Ngauruhoe and Taranaki would likely be less impactful. Ash falls from Ruapehu in 1945, 1975, 1995 and 1996 affected this region, as did Tongariro in 1896. Eruptions from White Island, in the Bay of Plenty, and other volcanoes are not likely to affect Hawke's Bay.
What Can You Do?
Have facemasks at the ready- large handkerchiefs or scarves are a reasonable substitute. Know how to disconnect any roof-fed water supply when an ash fall warning is given or ash begins to fall.
During an ash fall
- Listen to the radio for advice and information
- Stay indoors
- Close windows and doors
- Don't run air-conditioning or clothes driers with outside connections
- If outside, seek shelter; use a mask or handkerchief for breathing
- Disconnect roof-fed water supplies before ash falls
- If possible, keep your car under cover
- Don't drive unless you have to but if you must, drive slowly as ash fall will reduce visibility
- If you have driven in ash fall, check your air-filter, change your car oil and oil filter, and remove ash from windscreen wipers.
- Only pick up your children from school when requested. Schools will be notified about what emergency procedures they should take.
- Keep pets indoors
- Seek advice from Civil Defence if you are uncertain about what to do
After an ash fall
- Remove ash as soon as possible but remember ash particles commonly have sharp broken edges making it a very abrasive material.
- Clean house roofs first to reduce windblown ash covering cleaned areas. Repair damage to guttering and blocked down-pipes
- .Do not over-water or soak the ash as it will form a glue-like material (not easy to remove) and add weight to the roof. The best method is to lightly dampen the ash (to prevent it billowing) and sweep it up.
- Dampen and sweep ash from paths, driveways, and gutters.
- Do not dump ash in the stormwater or sewage system as it will set firmly and cause future problems and flooding on your property. Contact the Council for information on the disposal of ash.
- Place ash in rubbish bags if possible and seal them.
- Prevent further ash entering your house by only using the most protected entrance.
- Vacuum indoor surfaces where possible or use a damp cloth to remove ash. Avoid vigorous rubbing.
For a booklet and further details on the guidelines and preparedness before, during and after an ashfall go to www.ivhhn.org