Fire weather of a Canterbury Northwester on 6 February 2011 in South Island, New Zealand (original) (raw)

Foehn-Like Winds and Elevated Fire Danger Conditions in Southeastern Australia

Journal of Applied Meteorology and Climatology, 2010

Bushfires in southeastern Australia are a serious environmental problem, and consistently cause loss of life and damage to property and other assets. Understanding synoptic processes that can lead to dangerous fire weather conditions throughout the region is therefore an important undertaking aimed at improving community safety, protection of assets, and fire suppression tactics and strategies. In southeastern Australia severe fire weather is often associated with dry cool changes or coastally modified cold fronts. Less well known, however, are synoptic events that can occur in connection with the topography of the region, such as cross-mountain flows and foehn-like winds, which can also lead to abrupt changes in fire weather variables that ultimately result in locally elevated fire danger. This paper focuses on foehn-like occurrences over the southeastern mainland, which are characterized by warm, dry winds on the lee side of the Australian Alps. The characteristics of a number of ...

Ecology and long-term history of fire in New Zealand

2014

Fire is a complex physical and ecological process and one that has dramatically affected New Zealand's landscapes and ecosystems in the post-settlement era. Prior to human settlement in the late 13th century, the Holocene palaeoenvironmental record suggests that fire frequencies were low across most of New Zealand, with the notable exception of some wetland systems. Because few of New Zealand's indigenous plant species show any real adaptation to fire, the greatly increased fire activity that accompanied human settlement resulted in widespread, and in some cases permanent, shifts in the composition, structure and function of many terrestrial ecosystems. The combined effects of Maori and European fire have left long-lasting legacies in New Zealand's landscapes with the most obvious being the reduction of forest cover from 85-90% to 25% of the land area. Here we review the long-term ecological history of fire in New Zealand's terrestrial ecosystems and describe what is...

Initial Analysis of Fire Weather Characteristics between South-East Australia and South-West of Western Australia

Australia is a continent in which bushfires are an endemic part of the landscape. A bushfire can occur anywhere at some time of the year, restricted by the presence of flammable fuel, conducive weather conditions and an ignition source. Due to its size, Australia spans a wide range of geological and climatological zones, resulting in a large number of unique landscapes, from arid desert to rainforest to alpine, the genesis of a number of significant differences in fire weather between the east coast and west coast of the continent. The potential for disastrous fire is dictated by three factors that influence fire behaviour: (a) the type of vegetation (fuel) in which the fire is burning; (b) the weather; and (c) the topography in which the fire burns. This paper centers on (b) the weather, particularly the fire danger weathers measured by the McArthur Forest Fire Danger Index (FFDI). It concentrates on the comparison of fire danger weather conditions of southeast of Australia and southwest of Western Australia. Weather datasets since 1990 from almost all Automatic Weather Stations in Australia were acquired and 28 were selected and analysed. Furthermore, six sites were particularly chosen, one for each state/territory, for this comparison study. A number of fire danger severity measures were developed including the number of Extreme FFDI days per fire season and the longest number of consecutive Extreme FFDI days. The paper has a number of findings including the similarities of fire weather conditions of the two regions and their differences. This initial analysis motivates us to engage further research on other important fire risk factors such as vegetation, distribution of infrastructure, properties and population at risk, and possible correlation between the past fire ignitions including disastrous fire events and FFDI.

Verification of WRF modelled fire weather in the 2009–10 New Zealand fire season

International Journal of Wildland Fire, 2014

The Weather Research and Forecasting (WRF) mesoscale model was used to simulate the fire weather conditions for the 2009–10 wildland fire season in New Zealand. The suitability of WRF to simulate the high-end fire weather conditions for this period was assessed through direct comparison with observational data taken from 23 surface and two upper-air stations located across New Zealand. The weather variables and fire weather indices considered in the verification were the 1200 hours NZST air temperature, relative humidity, wind speed and direction, 24-h rainfall, New Zealand Fire Weather Index (FWI) and Continuous Haines Index (CHI). On observed high-end fire weather days, the model under-predicted the air temperatures and relative humidities, and over-predicted the wind speeds and 24-h rainfall at most weather stations. The results demonstrated that although WRF is suitable for modelling the air temperatures, there are issues with modelling the wind speeds and rainfall quantities. T...

Forest Fires and Wind Flow

Journal of the Japanese Society for Experimental Mechanics, 2014

Forest Fires and Wind Flow Hiroshi HAYASAKA In 2004, many large-scale fires occurred in Alaska and the burned area encompassed about 26,700 km. This was the largest burned area since 1956, and combined with an additional 19,000 km burned in 2005 (third-largest fire year), the total burned area comprised about 10% of the Alaskan boreal forest in just two years. To clarify the background of the many large-scale fires in 2004, spatial and temporal analyses using various data were performed in this paper. The derived results allow the following conclusion. Dry and warm weather conditions with strong persistent winds are crucial for fires. In 2004, easterly winds from Canada caused two daily hotspot peaks in late June and late August; one daily hotspot peak in mid-July was caused by southwesterly winds from Bethel or the Bristol Bay. These persistent winds lasted for about one week and promoted fire expansion. The above wind conditions in June and August were caused by the development of...

The 2017 Port Hills wildfires - a window into New Zealand's fire future?

2018

The Port Hills fire of February 2017 was New Zealand’s most devastating wildfire of recent times. Occurring on the outskirts of Christchurch city, it burned 1660 hectares, destroyed 9 homes and damaged 5 others, and resulted in the evacuation of more than 1400 residents from 450 households. If it were not for the efforts of firefighting agencies, the losses could have been very much greater. It is however worrying, when considered in the context of other significant rural-urban interface wildfires during the 2016/17 fire season, the trend of increasing house loss in New Zealand, and projections for future fire risk with climate change, that the Port Hills wildfire could become the norm that New Zealand fire agencies have to deal with. Now is the time to re-think the use of planning controls and homeowner education to mitigate future fire losses at the rural-urban

Frequency and impact of Holocene fire in eastern South Island, New Zealand

2007

Our evaluation of pre-settlement Holocene (10 000-1000 BP) fire, using radiocarbon-dated charcoals and pollen and charcoal spectra in pollen diagrams, concludes that fires were infrequent and patchy in the eastern South Island of New Zealand. Charcoal radiocarbon dates point to three broad phases of fire frequency: infrequent patchy fires from 10 000 to 2600 BP; a slightly increased frequency between 2600 and 1000 BP; and an unprecedented increase of fires after 1000 BP, which peaked between 800 and 500 BP. We suggest that natural fire was driven more by vegetation flammability (with ignitibility and combustibility components) than climate within this rain-shadow region, that plant chemistry principally determined fire frequency, and that topography determined the extent of fire. The review suggests that there were rare spatial and temporal instances of a feedback relationship between fire and early-successional grasses in eastern South Island. This occurred only within narrow-range, cool environments, whose equilibrium communities were of flammable, phenolic-rich woody species and grasses, and was predominantly in the late pre-settlement period. Elsewhere, grasses and herbs were understorey components to otherwise low-flammability, hardwood forest and scrub. ___________________________________________________________________________________________________________________________________

Anatomy of a catastrophic wildfire: The Black Saturday Kilmore East fire in Victoria, Australia

Forest Ecology and Management, 2012

The 7 February 2009 wildfires in south-eastern Australia burned over 450,000 ha and resulted in 173 human fatalities. The Kilmore East fire was the most significant of these fires, burning 100,000 ha in less than 12 h and accounting for 70% of the fatalities. We report on the weather conditions, fuels and propagation of this fire to gain insights into the physical processes involved in high intensity fire behaviour in eucalypt forests. Driven by a combination of exceedingly dry fuel and near-gale to gale force winds, the fire developed a dynamic of profuse short range spotting that resulted in rates of fire spread varying between 68 and 153 m min À1 and average fireline intensities up to 88,000 kW m À1 . Strong winds aloft and the development of a strong convection plume led to the transport of firebrands over considerable distances causing the ignition of spotfires up to 33 km ahead of the main fire front. The passage of a wind change between 17:30 and 18:30 turned the approximately 55 km long eastern flank of the fire into a headfire. Spotting and mass fire behaviour associated with this wide front resulted in the development of a pyrocumulonimbus cloud that injected smoke and other combustion products into the lower stratosphere. The benchmark data collected in this case study will be invaluable for the evaluation of fire behaviour models. The study is also a source of real world data from which simulation studies investigating the impact of landscape fuel management on the propagation of fire under the most severe burning conditions can be undertaken.