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Yahoo
08-07-2025
- Climate
- Yahoo
The science behind Texas' catastrophic floods
Rescue crews are scrambling to find survivors of catastrophic flooding that tore through Central Texas on the Fourth of July. It's already one of the deadliest flood events in modern American history, leaving at least 95 people dead, 27 of whom were girls and counselors at a Christian summer camp in Kerr County, which was inundated when the nearby Guadalupe River surged 26 feet in just 45 minutes. 'It's the worst-case scenario for a very extreme, very sudden, literal wall of water,' said Daniel Swain, a climate scientist at the University of California, Los Angeles, during a livestream Monday morning. 'I don't think that's an exaggeration in this case, based on the eyewitness accounts and the science involved.' It will take some time for scientists to do proper 'attribution' studies here, to say for instance how much extra rain they can blame on climate change. But generally speaking, this disaster has climate change's marks all over it — a perfect storm of conspiring phenomena, both in the atmosphere and on the ground. 'To people who are still skeptical that the climate crisis is real, there's such a clear signal and fingerprint of climate change in this type of event,' said Jennifer Francis, senior scientist at the Woodwell Climate Research Center. This tragedy actually started hundreds of miles to the southeast, out at sea. As the planet has warmed, the gulf has gotten several degrees Fahrenheit hotter. That's turned it into a giant puddle of fuel for hurricanes barreling toward the Gulf Coast, since those storms feed on warm seawater. Even when a hurricane isn't brewing, the gulf is sending more moisture into the atmosphere — think about how your bathroom mirror fogs up when you draw a hot bath. This pushes wet, unstable air higher and higher into the atmosphere, condensing into clouds. As these systems release heat, they grow even more unstable, creating a towering thundercloud that can drop extreme amounts of rainfall. Indeed, preceding the floods, the amount of moisture above Texas was at or above the all-time record for July, according to Swain. 'That is fairly extraordinary, in the sense that this is a place that experiences very moist air this time of year,' Swain said. That meant the system both had the requisite moisture for torrential rainfall, plus the instability that creates the thunderstorms that make that rain fall very quickly. This storm was dumping 2 to 4 inches of rain an hour, and it was moving very slowly, so it essentially stalled over the landscape — a gigantic atmospheric fire hose soaking Central Texas. Making matters worse, the ground in this part of Texas is loaded with limestone, which doesn't readily absorb rainwater compared to places with thick layers of soil at the surface. Rainwater rapidly flowed down hills and valleys and gathered in rivers, which is why the Guadalupe rose so fast. 'That means that not very much of the rain is going to soak into the ground, partly because the soil is shallow and partly because there's steep slopes in the terrain, so that water is able to run off fairly quickly,' said John Nielsen-Gammon, Texas' state climatologist and director of the Southern Regional Climate Center at Texas A&M University. This is exactly the kind of precipitation event that's increasing fastest in a warming climate, Swain added. In California, for instance, alternating periods of extremely wet conditions and extremely dry ones are creating 'weather whiplash.' As the world's bodies of water heat up, more moisture can evaporate into the atmosphere. And due to some basic physics, the warmer it gets, the more moisture the atmosphere can hold, so there's more potential for heavier rainfall. 'The Gulf of Mexico has been going through several marine heat waves recently, and so it's just adding that much more heat to the atmosphere, loading it up for more extreme rainfall events,' said Brett Anderson, senior meteorologist at AccuWeather. 'A lot of these places, 1-in-100-year floods may be becoming more like 1-in-50, even 1-in-10.' AccuWeather's preliminary estimate puts the economic damage of the flooding at between $18 billion and $22 billion. The Trump administration did make deep staffing cuts to the National Oceanic and Atmospheric Administration earlier this year, but it's too early to tell why some people didn't get warnings in time. The National Weather Service did indeed provide multiple flood warnings, and some people are reporting they got alerts on their cell phones, prompting them to escape. Still, with so many people dead or missing, they either didn't get the alerts or didn't adequately understand the danger they were in. Officials in Kerr County previously considered a more robust warning system for Guadalupe River floods, but rejected it as too expensive. For the girls and staff at the summer camp, the deluge arrived at the worst possible time, in the early hours of the morning while they slept. 'In my view — and this seems to be the consensus view of meteorologists — this is not really a failure of meteorology here,' Swain said. 'To my eye, the Weather Service predictions, they certainly weren't perfect, but they were as good as could have been expected given the state of the science.' Swain warns that if the administration follows through on its promises of further more cuts to NOAA, forecasts of flooding could well suffer. 'That really could be catastrophic,' he said. 'That will 100 percent be responsible for costing lives.' Grist has a comprehensive guide to help you stay ready and informed before, during, and after a disaster. Are you affected by the flooding in Texas and North Carolina? Learn how to navigate disaster relief and response. Get prepared. Learn how to be ready for a disaster before you're affected. Explore the full Disaster 101 resource guide for more on your rights and options when disaster hits. This story was originally published by Grist with the headline The science behind Texas' catastrophic floods on Jul 7, 2025.
Yahoo
07-07-2025
- Climate
- Yahoo
The Key Weather Ingredients That Fueled Texas' Deadly Floods
(Bloomberg) -- In Kerrville, Texas, it only rained five times in June, and July started off with just a couple of showers. In fact, the surrounding county was 100% in drought at the start of July. Are Tourists Ruining Europe? How Locals Are Pushing Back Foreign Buyers Swoop on Cape Town Homes, Pricing Out Locals Trump's Gilded Design Style May Be Gaudy. But Don't Call it 'Rococo.' Denver City Hall Takes a Page From NASA In California, Pro-Housing 'Abundance' Fans Rewrite an Environmental Landmark Ironically, that drought helped beget the deadly floods that swept through the region on Friday. It's one of a number of factors, including the abnormally hot Gulf of Mexico, that fueled a storm that killed 27 campers and counselors at Camp Mystic as well as dozens more across Texas. More than a foot of rain fell on Friday, sending the Guadalupe River and other waterways surging over their banks. While researchers haven't analyzed the storm that spawned the floods, extreme precipitation is becoming increasingly common as the planet warms. 'One of the clearest fingerprints of the climate crisis is the uptick in heavy rain events, like the one responsible for the tragedy in Texas this week,' said Jennifer Francis, a climate scientist at the Woodwell Climate Research Center. 'Texas is particularly flood-prone because the fever-hot Gulf of Mexico is right next door, providing plenty of tropical moisture to fuel storms when they come along.' As climate change warms the world, the atmosphere can hold more moisture. For every 1.8F (1C) increase in temperature, the air can carry about 7% more moisture. The mechanics are so well-studied, the formula for it has a name: the Clausius-Clapeyron equation, used to calculate the saturation of water vapor pressure to temperature, said Ryan Truchelut, president of commercial forecaster WeatherTiger. 'The carrying capacity increases faster and faster as the temperature increases,' he said. But that isn't the only issue fueling the mechanics of drought and flood. Warmer temperatures lead to more evaporation, particularly over the ocean. 'Human-caused increases in heat-trapping greenhouse gases have warmed oceans, which evaporate more moisture into the warmer air,' Francis said. 'Not only does this moisture increase rainfall, but it also fuels stronger storms.' The floods also got a boost from moisture flowing north from the remnants of Tropical Storm Barry, which had made landfall on Mexico's east coast a week ago, according to the National Weather Service. In Texas, the situation was also made worse by the drought because dry soils are less able to absorb water when it falls as rain, Truchelut said. Nearly 90% of Kerr County was in either extreme or exceptional drought — the two highest categories on the Drought Monitor's five-step scale — prior to the storm. 'Nothing is going into the parched dirt,' Truchelut said. Soil in that area of Texas isn't known for its water-absorbing qualities even in the best of times, said Tyler Roys, a meteorologist with AccuWeather Inc. When multiple inches of rain fall in an hour, as it did during the storm, 'the ground is going to absorb less,' he said. While the atmosphere is able to carry 7% more water vapor per 1.8F degree, that translates to a 2% to 3% increase in global average rain and snow, according to a review paper co-authored earlier this year by Daniel Swain, a climate scientist at the University of California at Los Angeles. This means a decrease in the number of light-to-moderate rainy days and an uptick in 'the overall number of dry days,' Swain wrote. But at the other end of the spectrum, days with the heaviest rainfall have increased. 'In other words: there's growing evidence not only that precipitation extremes will increase (in general) due to climate change – but also that the most intense, rarest & most dangerous rain events will increase faster than more 'moderate' extremes,' Swain wrote in a post on BlueSky. While there are signs that climate change may have contributed to the extreme rainfall in Texas, larger weather patterns that are typical for summer appear to have added to the volatility. High pressure across the US West and Great Plains led to a dearth of winds aloft to move thunderstorms across Texas, Roys said. That essentially allowed storms to park over the central part of the state, unloading rain over a relatively small geographic area. The storms — which continued into Monday — were part of a larger pattern that started to draw in moisture from the Gulf as well as all around the region, Truchelut said. This became a large rotating system of storms called a mesoscale convective storm complex, which fed off the warm, moist air. In the hours before the flood struck, the US Weather Prediction Center sent a series of mesoscale alerts warning rain could fall at rates of 3 inches (7.6 centimeters) per hour or more in the regions west of Interstate 35, which cuts through the heart of Austin. While natural patterns added to the dangers, Francis noted that cutting emissions would at least lower the risk of human-caused climate change. 'The horrific flooding in Texas is yet another glimpse into our future of more extreme weather, unless we kick our addiction to fossil fuels and stop deforestation,' she said. 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Time of India
07-07-2025
- Science
- Time of India
The mysterious black dust speeding up Arctic ice melt: What's behind it?
The Arctic, already warming nearly four times faster than the rest of the planet, faces a new and urgent threat: soot from Canada's record-breaking wildfires is darkening the region's ice and snow, potentially speeding up its melt at an alarming rate. This year, Canada has experienced one of its most severe wildfire seasons on record. According to the Canadian Interagency Forest Fire Centre , over 18 million hectares have burned so far in 2025, surpassing last year's devastating fires. The blazes have sent vast plumes of smoke and soot—known as black carbon—across North America and into the Arctic Circle. Why soot matters in the Arctic? Soot is a powerful climate forcer. When it settles on ice and snow, it reduces their reflectivity, or albedo, causing them to absorb more sunlight instead of reflecting it back into space. This leads to faster warming and melting—a process scientists call the 'albedo effect.' According to the National Snow and Ice Data Center, even a thin layer of black carbon can reduce snow's reflectivity by as much as 10%. Dr. Jennifer Francis, a senior scientist at the Woodwell Climate Research Center, explains: 'The Arctic is like the planet's air conditioner. When soot from wildfires lands on ice, it turbocharges melting. This creates a feedback loop: less ice means more warming, which means more fires and more soot.' Live Events Satellite imagery from NASA 's MODIS instrument shows a marked increase in darkened snow and ice surfaces across the Canadian Arctic Archipelago and Greenland's southern coast this summer. Preliminary data from the European Space Agency's Copernicus program indicate that concentrations of black carbon in the Arctic atmosphere have risen by over 30% compared to the 2010-2020 average. A recent study published in Nature Communications found that wildfire soot could account for up to 25% of the Arctic's recent sea ice loss, a figure that is likely to increase as wildfires become more frequent and intense. The consequences of accelerated Arctic melting are profound. Melting sea ice not only raises global sea levels but also disrupts weather patterns worldwide. The Intergovernmental Panel on Climate Change (IPCC) warns that rapid Arctic warming could destabilize the jet stream, leading to more extreme weather events across the Northern Hemisphere. Scientists are calling for urgent action to both curb greenhouse gas emissions and address the growing threat of wildfire soot. Enhanced monitoring, improved wildfire management, and international cooperation will be critical in protecting the Arctic's fragile climate system.
New Indian Express
17-06-2025
- Climate
- New Indian Express
Study finds planetary waves linked to wild summer weather have tripled since 1950
This essentially means the wave gets stuck for weeks on end, locked in place. As a result, some places get seemingly endless rain while others endure oppressive heat with no relief. 'A classic pattern would be like a high pressure out west (in the United States) and a low pressure back East and in summer 2018, that's exactly what we had,' Mann said. 'We had that configuration locked in place for like a month. So they (in the West) got the heat, the drought and the wildfires. We (in the East) got the excessive rainfall.' 'It's deep and it's persistent,' Mann said. 'You accumulate the rain for days on end or the ground is getting baked for days on end.' The study finds this is happening more often because of human-caused climate change, mostly from the burning of fossil fuels, specifically because the Arctic warms three to four times faster than the rest of the world. That means the temperature difference between the tropics and the Arctic is now much smaller than it used to be and that weakens the jet streams and the waves, making them more likely to get locked in place, Mann said. 'This study shines a light on yet another way human activities are disrupting the climate system that will come back to bite us all with more unprecedented and destructive summer weather events,' said Jennifer Francis, a climate scientist at the Woodwell Climate Research Center who wasn't involved in the research. 'Wave resonance does appear to be one reason for worsening summer extremes. On top of general warming and increased evaporation, it piles on an intermittent fluctuation in the jet stream that keeps weather systems from moving eastward as they normally would, making persistent heat, drought, and heavy rains more likely,' Francis said.
Yahoo
27-03-2025
- Science
- Yahoo
Arctic sea ice hits record low for its usual peak growth period
Arctic sea ice had its weakest winter buildup since record-keeping began 47 years ago, a symptom of climate change that will have repercussions globally, scientists said Thursday. The Arctic reaches its maximum sea ice in March each year and then starts a six-month melt season. The National Snow and Ice Data Center said the peak measurement taken Saturday was 5.53 million square miles (14.33 million square kilometers) — about 30,000 square miles (80,000 square kilometers) smaller than the lowest previous peak in 2017. That's a difference about the size of California. Scientists said warming conditions in the Arctic — the region is warming four times faster than the rest of the world — affect weather elsewhere. Pressure and temperature differences between north and south shrink. That weakens the jet stream, that moves weather systems along, making it dip further south with cold outbreaks and storms that often get stuck and rain or snow more, according to the snow and ice center and scientists such as Jennifer Francis of the Woodwell Climate Research Center in Cape Cod. 'The warming winter atmosphere above the Arctic Circle does impact large-scale weather patterns that do influence for those of us outside the Arctic,' said Julienne Stroeve, an ice scientist at the University of Manitoba. Of the smaller sea ice, Stroeve also noted that it's not only that there's less of it. The remaining ice is thin enough for more of it to melt quickly this summer, Stroeve said. She cautioned that a record low area in the winter doesn't guarantee a record small area in the summer. Melting Arctic sea ice — mostly in the summer — is making the polar bear population smaller, weaker and hungrier because they rely on the sea ice to hunt from, scientists said. Arctic sea ice's biggest year since record-keeping began was 1979, at 6.42 million square miles (16.64 million square kilometers). That means since satellites began tracking it, Arctic sea ice's winter peak has shrunk by about the size of Pakistan. 'This record low is yet another indicator of how Arctic sea ice has fundamentally changed from earlier decades,' said snow and ice data center scientist Walt Meier. He said sea ice extent is shrinking all four seasons. The five lowest amounts for winter peak Arctic sea ice have been since 2015. Earlier this month, Antarctica came close to breaking a record for record low sea ice — this is the time of year the region hits its minimum — and ended up with the second lowest sea level on record. ___ The Associated Press' climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP's standards for working with philanthropies, a list of supporters and funded coverage areas at
