Latest news with #naturalhazards
RNZ News
7 days ago
- Climate
- RNZ News
Thousands of Otago residents exposed to flooding, liquefaction, new report finds
Lateral spreading happens when liquefaction stretches and tears the ground. This example happened during the 2011 Christchurch earthquake. Photo: Sarah Bastin A new report has found thousands of people and buildings, including homes, are potentially exposed to flooding and liquefaction in Otago. The Otago Regional Council report used existing data to map the natural hazard exposure risks for people, buildings and critical services. It is the first comprehensive assessment for the entire region. The report found the greatest exposure was from river and lake flooding and liquefaction hazards. "Totals of greater than 30,000 people and buildings, including >10,000 dwellings, within the Otago region are located in areas identified as potentially subject to each of these hazards," the report said. Most of that exposure was located in and near Dunedin, with 39 of the 117 community areas being classed as having a 'high exposure' - which meant an area that had a high number of people or buildings within a mapped hazard area, not that an event was imminent. This included the floodplains that were in the council's and Lower Taieri flood protection schemes, but people and buildings within those areas were considered to be 'potentially exposed'. The report assessed 90 critical community facilities across the region - important buildings in a post-disaster response including hospitals, fire and police stations, or emergency operation centres. Of those, 23 were at risk of flooding and 35 were exposed to liquefaction across the region. Queenstown, Wānaka and Dunedin all had relatively high exposures to hazards involving slope stability including landslides and alluvial fans. There were about 500 people and 1100 buildings exposed to coastal hazards including tsunamis and storm surges, mostly around Dunedin and Clutha. The council's natural hazards manager, Dr Jean-Luc Payan, said the data would help to inform future planning to reduce risk. It would also show where they should prioritise future resilience and hazard investigations, as well as aid emergency management. "This work is not about predicting when an event might happen," he said. "It's about identifying where exposure exists so we can make smarter decisions about resilience, planning and investment." The council's senior natural hazards analyst, Tim van Woerden, said it was a living dataset that would continue to be refined as more detailed information was sourced. "These terms may sound technical or worrying, but it's important to remember this analysis is about where we focus effort to reduce exposure - not about predicting events or sounding alarms," he said. The council's natural hazards prioritisation programme is due to begin in the upcoming financial year.
Fast Company
28-05-2025
- Climate
- Fast Company
Tornado Alley is shifting east. Here's what to know
Violent tornado outbreaks, like the storms that tore through parts of St. Louis and London, Kentucky, on May 16, have made 2025 seem like an especially active, deadly and destructive year for tornadoes. The U.S. has had more reported tornadoes than normal—more than 960 as of May 22, according to the National Weather Service's preliminary count. That's well above the national average of around 660 tornadoes reported by that point over the past 15 years, and it's similar to 2024—the second-most-active year over that same period. I'm an atmospheric scientist who studies natural hazards. What stands out about 2025 so far isn't just the number of tornadoes, but how Tornado Alley has encompassed just about everything east of the Rockies, and how tornado season is becoming all year. Why has 2025 been so active? The high tornado count in 2025 has a lot to do with the weather in March, which broke records with 299 reported tornadoes —far exceeding the average of 80 for that month over the past three decades. March's numbers were driven by two large tornado outbreaks: About 115 tornadoes swept across more than a dozen states March 14 to 16, stretching from Arkansas to Pennsylvania; and 145 tornadoes hit March 31 to April 1, primarily in a swath from Arkansas to Iowa and eastward. The 2025 numbers are preliminary pending final analyses. While meteorologists don't know for sure why March was so active, there were a couple of ingredients that favor tornadoes: First, in March the climate was in a weak La Niña pattern, which is associated with a wavier and stormier jet stream and, often, with more U.S. tornadoes. Second, the waters of the Gulf were much warmer than normal, which feeds moister air inland to fuel severe thunderstorms. By April and May, however, those ingredients had faded. The weak La Niña ended and the Gulf waters were closer to normal. April and May also produced tornado outbreaks, but the preliminary count over most of this period, since the March 31 to April 1 outbreak, has actually been close to the average, though things could still change. What has stood out in April and May is persistence: The jet stream has remained wavy, bringing with it the normal ebb and flow of stormy low-pressure weather systems mixed with sunny high-pressure systems. In May alone, tornadoes were reported in Colorado, Minnesota, Delaware, Florida, and just about every state in between. Years with fewer tornadoes often have calm periods of a couple of weeks or longer when a sunny high-pressure system is parked over the central U.S. However, the U.S. didn't really get one of those calm periods in spring 2025. Tornado Alley shifts eastward The locations of these storms have also been notable: The 2025 tornadoes through May have been widespread but clustered near the lower and central Mississippi Valley, stretching from Illinois to Mississippi. That's well to the east of traditional Tornado Alley, typically seen as stretching from Texas through Nebraska, and farther east than normal. April through May is still peak season for the Mississippi Valley, though it is usually on the eastern edge of activity rather than at the epicenter. The normal seasonal cycle of tornadoes moves inland from near the Gulf Coast in winter to the upper Midwest and Great Plains by summer. Over the past few decades, the U.S. has seen a broad shift in tornadoes in three ways: to the east, earlier in the year, and clustered into larger outbreaks. Winter tornadoes have become more frequent over the eastern U.S., from the southeast, dubbed Dixie Alley for its tornado activity in recent years, to the Midwest, particularly Kentucky, Illinois, and Indiana. Meanwhile, there has been a steady and stark decline in tornadoes in the 'traditional' tornado season and region: spring and summer in general, especially across the Great Plains. It may come as a surprise that the U.S. has actually seen a decrease in overall U.S. tornado activity over the past several decades, especially for intense tornadoes categorized as EF2 and above. There have been fewer days with a tornado. However, those tornado days have been producing more tornadoes. These trends may have stabilized over the past decade. Deadlier tornadoes This eastward shift is likely making tornadoes deadlier. Tornadoes in the Southeastern U.S. are more likely to strike overnight, when people are asleep and cannot quickly protect themselves, which makes these events dramatically more dangerous. The tornado that hit London, Kentucky, struck after 11 p.m. Many of the victims were older than 65. The shift toward more winter tornadoes has also left people more vulnerable. Since they may not expect tornadoes at that time of year, they are likely to be less prepared. Tornado detection and forecasting is rapidly improving and has saved thousands of lives over the past 50-plus years, but forecasts can save lives only if people are able to receive them. This shift in tornadoes to the east and earlier in the year is very similar to how scientists expect severe thunderstorms to change as the world warms. However, researchers don't know whether the overall downward trend in tornadoes is driven by warming or will continue into the future. Field campaigns studying how tornadoes form may help us better answer this question. Remember that it only takes one For safety, it's time to stop focusing on spring as tornado season and the Great Plains as Tornado Alley. Tornado Alley is really all of the U.S. east of the Rockies and west of the Appalachians for most of the year. The farther south you live, the longer your tornado season lasts. Forecasters say it every year for hurricanes, and we badly need to start saying it for tornadoes too: It only takes one to make it a bad season for you or your community. Just ask the residents of London, Kentucky; St. Louis; Plevna and Grinnell, Kansas; and McNairy County, Tennessee. if you hear sirens or are under a tornado warning, immediately go to your safe space. A tornado may already be on the ground, and you may have only seconds to protect yourself.
Yahoo
24-05-2025
- Climate
- Yahoo
Tornado Alley has become almost everything east of the Rockies — and it's been a violent year
A deadly tornado hit London, Ky., on May 16, 2025, just a few weeks after another tornado outbreak in the state. (Allison Joyce/AFP/Getty Images) Violent tornado outbreaks, like the storms that tore through parts of St. Louis and London, Kentucky, on May 16, have made 2025 seem like an especially active, deadly and destructive year for tornadoes. The U.S. has had more reported tornadoes than normal — over 960 as of May 22, according to the National Weather Service's preliminary count. That's well above the national average of around 660 tornadoes reported by that point over the past 15 years, and it's similar to 2024 — the second-most active year over that same period. I'm an atmospheric scientist who studies natural hazards. What stands out about 2025 so far isn't just the number of tornadoes, but how Tornado Alley has encompassed just about everything east of the Rockies, and how tornado season is becoming all year. The high tornado count in 2025 has a lot to do with the weather in March, which broke records with 299 reported tornadoes — far exceeding the average of 80 for that month over the past three decades. March's numbers were driven by two large tornado outbreaks: about 115 tornadoes swept across more than a dozen states March 14-16, stretching from Arkansas to Pennsylvania; and 145 tornadoes hit March 31 to April 1, primarily in a swath from Arkansas to Iowa and eastward. The 2025 numbers are preliminary pending final analyses. While meteorologists don't know for sure why March was so active, there were a couple of ingredients that favor tornadoes: First, in March the climate was in a weak La Niña pattern, which is associated with a wavier and stormier jet stream and, often, with more U.S. tornadoes. Second, the waters of the Gulf were much warmer than normal, which feeds moister air inland to fuel severe thunderstorms. By April and May, however, those ingredients had faded. The weak La Niña ended and the Gulf waters were closer to normal. April and May also produced tornado outbreaks, but the preliminary count over most of this period, since the March 31-April 1 outbreak, has actually been close to the average, though things could still change. What has stood out in April and May is persistence: The jet stream has remained wavy, bringing with it the normal ebb and flow of stormy low-pressure weather systems mixed with sunny high-pressure systems. In May alone, tornadoes were reported in Colorado, Minnesota, Delaware, Florida and just about every state in between. Years with fewer tornadoes often have calm periods of a couple of weeks or longer when a sunny high-pressure system is parked over the central U.S. However, the U.S. didn't really get one of those calm periods in spring 2025. The locations of these storms have also been notable: The 2025 tornadoes through May have been widespread but clustered near the lower and central Mississippi Valley, stretching from Illinois to Mississippi. That's well to the east of traditional Tornado Alley, typically seen as stretching from Texas through Nebraska, and farther east than normal. April through May is still peak season for the Mississippi Valley, though it is usually on the eastern edge of activity rather than at the epicenter. The normal seasonal cycle of tornadoes moves inland from near the Gulf Coast in winter to the upper Midwest and Great Plains by summer. Over the past few decades, the U.S. has seen a broad shift in tornadoes in three ways: to the east, earlier in the year and clustered into larger outbreaks. Winter tornadoes have become more frequent over the eastern U.S., from the southeast, dubbed Dixie Alley for its tornado activity in recent years, to the Midwest, particularly Kentucky, Illinois and Indiana. Meanwhile, there has been a steady and stark decline in tornadoes in the 'traditional' tornado season and region: spring and summer in general, especially across the Great Plains. It may come as a surprise that the U.S. has actually seen a decrease in overall U.S. tornado activity over the past several decades, especially for intense tornadoes categorized as EF2 and above. There have been fewer days with a tornado. However, those tornado days have been producing more tornadoes. These trends may have stabilized over the past decade. This eastward shift is likely making tornadoes deadlier. Tornadoes in the Southeastern U.S. are more likely to strike overnight, when people are asleep and cannot quickly protect themselves, which makes these events dramatically more dangerous. The tornado that hit London, Kentucky, struck after 11 p.m. Many of the victims were over age 65. The shift toward more winter tornadoes has also left people more vulnerable. Since they may not expect tornadoes at that time of year, they are likely to be less prepared. Tornado detection and forecasting is rapidly improving and has saved thousands of lives over the past 50-plus years, but forecasts can save lives only if people are able to receive them. This shift in tornadoes to the east and earlier in the year is very similar to how scientists expect severe thunderstorms to change as the world warms. However, researchers don't know whether the overall downward trend in tornadoes is driven by warming or will continue into the future. Field campaigns studying how tornadoes form may help us better answer this question For safety, it's time to stop focusing on spring as tornado season and the Great Plains as Tornado Alley. Tornado Alley is really all of the U.S. east of the Rockies and west of the Appalachians for most of the year. The farther south you live, the longer your tornado season lasts. Forecasters say it every year for hurricanes, and we badly need to start saying it for tornadoes too: It only takes one to make it a bad season for you or your community. Just ask the residents of London, Kentucky; St. Louis; Plevna and Grinnell, Kansas; and McNairy County, Tennessee. Listen to your local meteorologists so you will know when your region is facing a tornado risk. And if you hear sirens or are under a tornado warning, immediately go to your safe space. A tornado may already be on the ground, and you may have only seconds to protect yourself. This article is republished from The Conversation under a Creative Commons license. Read the original article. Dan Chavas is an associate professor of atmospheric science at Purdue University. Through its opinion section, Kansas Reflector works to amplify the voices of people who are affected by public policies or excluded from public debate. Find information, including how to submit your own commentary, here.
RNZ News
06-05-2025
- General
- RNZ News
Moving towns: 4 stories of communities facing relocation show the complex realities of managed retreat
By Stacy Vallis, Andrew Burgess, Ann Morrison, Imelda Piri and Priscila Bean* of The Ōpāwaho Heathcote River burst its banks during heavy rainfall last week. Natural hazards have long shaped our cities, the authors say. Photo: RNZ/Marika Hill Analysis : With large parts of New Zealand having recently been pummelled by ex-tropical Cyclone Tam and ongoing bouts of heavy rain, it is important to remember that natural hazards have long shaped our cities. Two townships in particular - Westport and Kumeū - have featured in national stories about floods since the 19th century. They are now among a growing number of places where flooding infrastructure is losing effectiveness and drastic actions have to be considered, including managed retreat. This raises understandable concerns about anticipated drops in land value and loss of social connection to a place. But managed or planned retreat is not a new concept nationally or globally. International examples can serve as useful references. These stories from four communities in three countries show how connection to culture and place can be either challenged or sustained when relocation becomes necessary. Back in 1956, the Australian township of Tallangatta in north-eastern Victoria was forced to move eight kilometres west because of the expansion of the Hume Weir. Originally, "old" Tallangatta was located at the meeting point of the Mitta Mitta River and the Tallangatta Creek. But this was subsumed by a significant water-storage facility, the Hume Dam (Lake Hume). During periods of low water levels, it is still possible to view the remains of the old town from a lookout. About a hundred houses and a few shops were relocated, including some Victorian buildings. Residents said there was no cost to the relocation, with relocated houses repainted and given modern plumbing facilities that did not previously exist. New public and commercial buildings were designed in the modernist architectural style of the era, and in 2016 Tallangatta was acknowledged as a "notable town" by the National Trust of Victoria. The blend of Victorian and mid-century modernist buildings characterises the new township and represents different eras in its history, including the physical and social upheaval of relocation. But while it can be possible to physically move timber buildings to a new site, characteristics such as original township layout and social connection to the surrounding landscape can be lost. Sweden's northernmost town of Kiruna faces a similar situation due to land subsidence caused by a huge iron ore mine. Its 18,000 inhabitants now have to move about three kilometres east. The town's rich cultural heritage includes a long Indigenous Sami history and a long period of industrial growth driven by the mine which saw it given national heritage recognition in the 1980s. The relocation process has not been without its challenges. One big question was how many historic buildings to move to help retain authentic connections to place. It was proposed that new building design would use the aesthetic qualities of the historic buildings. And there was discussion about either creating an "old town" within the site, or dispersing relocated buildings around the town. Eventually, local representatives and the mining company (which funded the relocation) decided about 50 of the oldest buildings would be relocated while the remainder would be demolished. Demolition has now taken place, along with construction of a new town hall to replace its predecessor, a heritage-listed building dating to 1964. Such decisions call for careful balancing of the impacts on local Indigenous cultural heritage, the economic role the mine has played in the town's expansion, and its contribution to iron production in Europe in general. A view of Kumeū from a helicopter during 2021 floods. Photo: Supplied / Christaan Head Climate change is making floods more intense and frequent. New Zealand's South Island town of Westport is a 19th-century coal mining and trading settlement that experienced severe flooding in July 2021 and again in February 2022. Although these floods were no larger than ones recorded in the past, their impact on homes and infrastructure was significantly greater due to Westport's expansion over the years. The July 2021 flood damaged more than 500 houses, resulting in a NZ$54 million flood protection plan. In 2023, the Buller District Council initiated a master plan to guide Westport's future growth and development. It focuses on the controlled expansion of the township to higher ground on government-owned Pāmu farmland one kilometre southwest of Westport. Flooding in Westport in July, 2021. Photo: Supplied/NZ Defence Force The council endorsed Westport's master plan in March this year, but some residents are still apprehensive about the changes . In the North Island, the township of Kumeū is close to Auckland, the country's biggest city, but still reflects its farming history. Following recent floods, as well as several major floods since 1926, Auckland Council and local leaders joined forces to devise a plan to improve the town's resilience. While the prospect of managed retreat has been raised, proactive river maintenance seems the preferred option, including regular debris clearance by local contractors to optimise storm water drainage. Managed retreat presents opportunities for improvement to Kumeū's infrastructure. But the long-established cultural relationships between people and landscapes in Aotearoa New Zealand also need to inform inclusive decisions about major relocations. Connection to heritage rests on relationships with place and setting. These can include buildings, landscapes and views, as well as the historical and cultural values associated with a given site. * Stacy Vallis is a Lecturer in Architecture and Emerging Technologies, Auckland University of Technology; Andrew Burgess is a Senior Lecturer in Architecture, Auckland University of Technology; Ann Morrison is an Associate Professor in Interactive Design, Auckland University of Technology; Imelda Piri is a Lecturer in Built Environments Engineering, Auckland University of Technology; Priscila Besen is a Lecturer in Sustainable Architecture, Auckland University of Technology. This article was first published by The Conversation .
