Extreme heat is back — here's where it will be the worst
Some cities could notch their highest temperatures of the year as heat builds from the South to the Midwest this week while humidity drives the heat index, or how hot it will actually feel, well into the triple digits.
Sizzling conditions began to set up from the Gulf Coast to the Plains on Tuesday, with more than 60 million people under heat alerts from Florida to South Dakota. Cities across these regions, including Memphis, Atlanta and St. Louis, saw temperatures climb into the 90s Tuesday afternoon.
Heat remains the deadliest form of extreme weather in the US. Globally, heat waves are becoming more frequent, more severe and lasting longer as the world warms due to fossil fuel-driven climate change.
The heat will ramp up in intensity and expand to the Midwest on Wednesday. Brutal temperatures will stretch from the South through the Midwest on Thursday and also start to push into the East.
Wednesday and Thursday could be the new hottest days of the year in cities like Chicago, St. Louis and Memphis: Chicago and St. Louis are expected to soar into the upper 90s both days while Memphis could flirt with the triple digit mark.
Unlike the intense heat wave earlier this summer, this bout of stifling heat isn't likely to topple hundreds of records. But records don't need to fall for heat to be incredibly dangerous: A Level 3 of 4 heat risk stretches from the Gulf Coast to Michigan's Upper Peninsula on Wednesday, and pockets along the Mississippi Valley and Gulf Coast are under a Level 4 of 4 'extreme' risk that will linger through Thursday.
Heat this severe impacts anyone without access to effective cooling or proper hydration, not just vulnerable populations, according to the National Oceanic and Atmospheric Administration. And for those without air conditioning, staying indoors can become deadly during the hottest parts of the day, the agency warns. For those under the highest risk level, the heat dangers are heightened because there will be little to no overnight relief.
The heat index — also known as the apparent temperature — will soar to dangerous levels for tens of millions this week.
Heat indices soared into the triple digits across the South and parts of the Central Plains on Tuesday. Temperatures felt as high as 110 degrees along coastal Georgia and South Carolina in the afternoon.
By Wednesday, some parts of the Mississippi Valley, including Memphis, could have a heat index of between 110 and 115 degrees.
Humid conditions will also prevent temperatures from cooling significantly overnight. It could still be close to 80 degrees in St. Louis by sunrise Thursday — nearly 10 degrees higher than a typical low for July. Chicago is expected to see low temperatures in the upper 70s Thursday morning, a departure from the typical lows in the 60s for this time of year.
When overnight temperatures don't cool down enough to offer relief for overheated bodies, people are at greater risk for heat-related illnesses. Nighttime temperatures are taking the hardest hit from climate change, warming faster than daytime highs.
The heat will ramp up considerably Thursday in parts of the Ohio Valley and start to reach into the Northeast. Detroit, Cleveland and Cincinnati could come within a degree of or match their hottest day of the year so far, with expected highs in the 90s. These highs are about 10 degrees hotter than what's typical even in this hottest month of the year.
The most intense heat for the East Coast will arrive by Friday, with high temperatures in the middle to upper 90s and a heat index of 100 degrees or more possible for Washington, DC, Philadelphia, New York City and Boston. High temperatures in this range are also up to 10 degrees hotter than typical for these cities.
Climate change is making this week's heat wave at least three times more likely for nearly 160 million people, almost half the US population, when compared with a world without fossil fuel emissions, according to an analysis from the climate research nonprofit Climate Central.
The heat dome will ease by Saturday for many, replaced by more typical, though still very toasty, late July temperatures.
Here's how hot this summer has been so far
For many in the contiguous US, it's been sweltering since meteorological summer — June through August — began. The bulk of the heat has been focused on the East, where dozens of locations are so far on track for their hottest summer to date.
Many more locales are currently experiencing at least one of their 10-hottest summers to date. The Northeast, Mid-Atlantic, Ohio Valley and Midwest have all been literal hotspots.
Rather than searing daytime temperatures driving the above-average heat in these locations, it's been many, many instances of too-warm overnight lows making the biggest impact, according to a CNN analysis of data from NOAA's National Climatic Data Center.
The Plains have so far dodged this really hot summer. Much of the West has too, with a few exceptions: Seattle is having its fifth-warmest summer to date while Portland is hovering around seventh-highest.
Tiny pockets of cooler-than-normal summers are few and far between in the US, but the San Francisco Bay Area in California is one of them. Parts of the Bay Area — including Oakland and Fremont — are experiencing one of their coolest summers to date.
August will likely be another hot month for much of the country, according to the Climate Prediction Center's latest forecast. Cities that are already baking could continue their hot streak while other places that have escaped the worst could still warm up a bit in the latter part of summer.
CNN's Luke Snyder contributed to this report.
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Gizmodo
2 hours ago
- Gizmodo
Floods and Other Disasters Kill More People at Night, but Not for the Reasons You Think
It was 4 a.m. on July 4 at Camp La Junta in Kerr County when Kolton Taylor woke up to the sound of screaming. The 12-year-old boy stepped out of bed and straight into knee-deep floodwaters from the nearby Guadalupe River. Before long, the water had already risen to his waist. In the darkness, he managed to feel for his tennis shoes floating nearby, put them on, and escape to the safety of the hillside. All 400 people at the all-boys camp survived, even as they watched one of their cabins float away in the rushing river. But 5 miles downriver at Camp Mystic, 28 campers and counselors were killed. The flash flooding in Texas would have been catastrophic at any time of day, but it was especially dangerous because it happened at night. Research shows that more than half of deaths from floods happen after dark, and in the case of flash floods, one study put the number closer to three-quarters. Other hazards are more perilous in the dark, too: Tornadoes that strike between sunset and sunrise are twice as deadly, on average, as those during the day. No one can stop the sun from rising and setting, but experts say there are simple precautions that can save lives when extreme weather strikes at night. As climate change supercharges floods, hurricanes, and fires, it's becoming even more important to account for the added risks of nocturnal disasters. Stephen Strader, a hazards geographer at Villanova University, said that at night, it's not enough to rely on a phone call from a family member or outdoor warning sirens (which Kerr County officials discussed installing, but never did). The safest bet is a NOAA radio, a device that broadcasts official warnings from the nearest National Weather Service office 24/7. One major advantage is that it doesn't rely on cell service. 'That's old school technology, but it's the thing that will wake you up and get you up at 3 a.m.,' said Walker Ashley, an atmospheric scientist and disaster geographer at Northern Illinois University. Even with warning, reacting in the middle of the night isn't easy. When people are shaken awake, they're often disoriented, requiring additional time to figure out what's happening before they can jump into action. 'Those precious minutes and seconds are critical a lot of times in these situations for getting to safety,' Strader said. The darkness itself presents another issue. People tend to look outside for proof that weather warnings match up with their reality, but at night, they often can't find the confirmation they're looking for until it's too late. Some drive their cars into floodwaters, unable to see how deep it is, and get swept away. It's also harder to evacuate—and try to rescue people—when you can barely see anything. 'I invite anybody to just go walk around the woods with a flashlight off, and you find out how difficult it can be,' Ashley said. 'Imagine trying to navigate floodwaters or trying to find shelter while you're in rushing water at night with no flashlight. It's a nightmare.' The logic applies to most hazards, but the night problem appears the worst with sudden-onset disasters like tornadoes and earthquakes—and the early-morning flash floods in Texas, where the Guadalupe rose 26 feet in 45 minutes. A warmer atmosphere can hold more moisture, meaning that storms can dump more water more suddenly than they used to. 'We have essentially, because of climate change, put the atmosphere on steroids,' Strader said. It's on his to-do list to study whether other disasters, like hurricanes and wildfires, are deadlier at night. When Hurricane Harvey pummeled Texas with rain for days in 2017, people described waking up to water creeping into their homes; the Texas National Guard navigated rescue boats through neighborhoods in the dark, searching for survivors. In recent years, hurricanes have rapidly intensified before making landfall, fueled by warmer ocean waters. That shrinks the window in which forecasters can warn people a strong storm is coming. To compound the problem, at the end of July, the Pentagon plans to stop sharing the government satellite microwave data that helps forecasters track hurricanes overnight, leaving the country vulnerable to what's called a 'sunrise surprise.' While daytime tornado deaths have declined over time, nighttime fatalities are on the rise, Strader and Ashley have found in their research. (It's still unclear as to how climate change affects tornadoes.) They found that tornadoes that touch down at night are statistically more likely to hit someone, simply because there are more potential targets scattered across the landscape. During the day, people are often concentrated in cities and sturdy office buildings versus homes, which may be manufactured and not as structurally resilient to floods or high winds. Night adds dimensions of danger to many types of disasters, but the darkness isn't the only factor at play—and it doesn't have to be as deadly, Ashley said, stressing the importance of getting a weather radio and making a plan in case the worst happens. 'Have multiple ways to get information, and your odds of survival are extremely high, even in the most horrific tornado situation.' This article originally appeared in Grist at Grist is a nonprofit, independent media organization dedicated to telling stories of climate solutions and a just future. Learn more at
Yahoo
2 hours ago
- Yahoo
It's not your imagination: Winnipeg summers are smokier than they used to be
Feel like the past few Winnipeg summers have been smokier than usual? Turns out, there's data to back that up. The last several summers have been some of Canada's smokiest on record, as wildfires burn bigger, hotter and earlier in the season than had been normal in previous decades. Amid the worst wildfire season in Manitoba in three decades, at this pace Winnipeg could break its own nearly 65-year-old smoke record this year. "We do see this increasing, and some of it can be attributed to climate change, or drought, or the heat," said Céline Audette, manager for health and air quality forecast services at Environment and Climate Change Canada. The agency has been tracking smoke in the city's air since 1953. And while the smokiest summer on record came way back in 1961, that was a rare occurrence for the era that coincided with a historic summer drought and more than one million hectares of forest burned. Lately, smoky summers have been a more frequent occurrence. "With increasing temperatures and increasing heat in many areas of the country, we will have also an increasing number of forest fires," Audette said. WATCH | Winnipeg summers getting smokier, data suggests: And with an increasing number of forest fires, there will also be an increasing number of what are known as "smoke hours," she said. It's a measure Environment and Climate Change Canada defines as a period when visibility drops to 9.7 kilometres (six statute miles) or less due to smoke, as measured hourly by some of its weather-monitoring stations — including one near the Winnipeg airport. For decades, 1961 stood out as the only year that saw more than 100 total smoke hours in Winnipeg during wildfire season (May to September). More recently, however, that amount of smoke has become the norm. Four of the past five years have seen 100 smoke hours or more. The chart below shows total smoke hours each year, including so far in 2025. The data in this chart is updated daily, so you can check back throughout the summer to see how it compares to past years — and whether Winnipeg breaks the record set in 1961. As of mid-July, 2025 was already the third-smokiest season on record. A disadvantage of the "smoke hour" measure — as compared to more nuanced air-quality index scores or detailed fine-particulate matter readings — is that it doesn't tell you exactly how smoky it is. But the advantage is that Environment and Climate Change Canada has been tracking "smoke hours" this way for the better part of a century, allowing us to compare our current smoky skies to those of Winnipeggers long in the past. Another advantage: it tracks naturally with our intuitive experience. Was it smoky just in the morning, or all day? Was it smoky just for a day or two? All week? The calendar-style chart below depicts smoke this wildfire season. Each dot in the chart represents a day, and the colour of each dot depicts how many smoke hours there were that day. Darker dots mean more smoke hours — and in July, the two darkest are July 11 and 12, when advisories were issued as thousands attended Winnipeg Folk Festival. Wildfire smoke in past seasons Using this same approach, we can peer back into past wildfire seasons, at a glance. The final chart below depicts each season as a horizontal band. Each day is a coloured line on that band. The colour of each bar represents the number of smoke hours that day. It makes for a tall chart. But as you scroll down, you can quickly see how Winnipeg's air looked in recent years compared to the 2010s, 2000s, 1990s, 1980s, 1970s, 1960s and 1950s. Different kinds of smoke It's important to note that not all of the smoke picked up in this measure since 1953 necessarily comes from wildfires. Smoke from other sources, such as stubble burning on nearby agricultural land, would also register in the data. The practice was more common in the past, before the Manitoba Government began regulating it in 1993, after a particularly brutal blanket of smoke enveloped parts of the province in October 1992. Effects of smoke Dr. Anna Gunz said smoke may affect health in the long term in similar ways to exposure to other forms of air pollution, which can impact heart, lung and brain health. "Some of this obviously we don't know yet from wildfires, but ... it seems like exposure to wildfire smoke can affect prenatal outcomes, including low birth weight and potentially prematurity," Gunz, an environmental health pediatrician and professor at Western University, recently told Information Radio host Marcy Markusa. "We know there are long-term health consequences that these infants are now at risk of." The Weather CAN app is one place you can check for air quality index scores before heading outside. Source of smoke The following map also provides a visual sense of where any smoke currently in the sky is originating. Environment Canada tracks one of the main pollutants in wildfire smoke, known as fine particulate matter or PM2.5, and how it's circulating in the air. Below, you can see a map showing the latest smoke plumes circulating over North America. You can scroll around and zoom in on the map to take a closer look at Winnipeg or any specific area.


WIRED
3 hours ago
- WIRED
The Texas Floods Were a Preview of What's to Come
Jul 26, 2025 7:00 AM Mounting evidence shows no US state is safe from the flooding that ravaged Texas' Kerr Country. Community members grieve during a candlelight vigil to honor the lives lost in the flash floods that claimed more than 120 lives on July 11, 2025 in Kerrville, Texas. Photograph:This story originally appeared on Grist and is part of the Climate Desk collaboration. The country watched in horror as torrential rain drenched Texas earlier this month, sweeping at least 135 people to their death. Kerr County alone lost 107, including more than two dozen children at Camp Mystic. From afar, it would be easy, even tempting, to think that floods like these could never happen to you. That the disaster is remote. It's not. As details of the tragedy have come into focus, the list of contributing factors has grown. Sudden downpours, driven by climate change. The lack of a comprehensive warning system to notify people that the Guadalupe River was rising rapidly. Rampant building in areas known to flood, coupled with incomplete information about what places might be at risk. These are the same elements that could trigger a Kerr County type of catastrophe in every state in the country. It's a reality that has played out numerous times already in recent years, with flooding in Vermont, Kentucky, North Carolina and elsewhere, leaving grief and billions of dollars in destruction in its wake. 'Kerr County is an extreme example of what's happening everywhere,' said Robert Freudenberg, vice president of energy and environmental programs at the Regional Plan Association. 'People are at risk because of it, and there's more that we need to be doing.' The most obvious problem is we keep building in areas prone to flooding. The Federal Emergency Management Agency, or FEMA, produces readily available maps showing high-risk locales. Yet, according to the latest data from the nonprofit climate research firm First Street Foundation, 7.9 million homes and other structures stand in a FEMA Special Flood Hazard Area, which designates a location with 1 percent or greater chance of being inundated in any given year. FEMA Flood Zone Top 10 Source: First Street Foundation In Louisiana, a nation-leading 23 percent of properties are located in a FEMA flood zone. In Florida, it's about 17 percent. Arkansas, New Mexico, and Nebraska are perhaps less expected members of the top 10, as is New Jersey, which, with New York City, saw torrential rain and flooding that killed two people earlier this month. Texas ranks seventh in the country, with about 800,000 properties, or roughly 6.5 percent of the state's total, sitting in a flood zone. Kerr County officials have limited authority to keep people from building in these areas, but even when governments have the ability to prevent risky building projects, they historically haven't. Although one study found that some areas are finally beginning to curb floodplain development, people keep building in perilous places. 'There's an innate draw to the water that we have, but we need to know where the limits are,' said Freudenberg. 'In places that are really dangerous, we need to work toward getting people out of harm's way.' Kerr County sits in a region known as Flash Flood Alley, and at least four cabins at Camp Mystic sat in an extremely hazardous 'floodway.' Numerous others stood in the path of a 100-year flood. When the Christian summer camp for girls underwent an expansion in 2019, the owners built even more cabins in the water's path. 'It's an unwillingness to think about what the future—and the present—have in store for us,' said Rob Moore, director of the Water and Climate Team at the Natural Resources Defense Council, or NRDC, about Americans' tradition of floodplain development. 'It's a reluctance to own up to the reality we live in.' Many people don't even know they are in harm's way. According to the NRDC, 14 states have no flood disclosure laws, and in eight they deem the laws 'inadequate.' FEMA maps are also flawed. For one, they can be politically influenced, with homeowners and communities often lobbying to be excluded in order to avoid insurance mandates and potential building costs. And experts say the science underpinning the maps is lagging too. FEMA 'only maps main river channels and coastal storm surge areas,' explained Jeremy Porter, the head of climate implications research at First Street Foundation. The agency, he added, specifically doesn't model heavy rainfall, isn't great about indicating the risk of urban flooding, and is behind on accounting for climate change. First Street Flood Zone Top 10 Source: First Street Foundation First Street built a flood model that tries to fill in those gaps. It found that 17.7 million people are at risk of a 100-year flood, a number that's more than double what FEMA's hazard area state rankings also change, with mountainous areas susceptible to inland flash flooding jumping up the list. West Virginia moves into first, with a staggering 30 percent of properties built in flood-prone areas. Kentucky climbs from 19th to sixth. Texas remains at seventh, but the portion of properties at risk goes to 15 percent. In Kerr County, FEMA's maps showed 2,560 properties (6.5 percent) in a flood zone. First Street's model nearly doubled that. 'There's a ton of unknown risk across the country,' said Porter, who says better maps are among the most important goals that policymakers can and should work toward. First Street has partnered with the real estate website Redfin to include climate risk metrics in its listings. Rob Moore says political will is essential to making that type of systemic change when it comes to not only flooding, but other climate risks, such as wildfires or coastal erosion. Strengthening building codes and restricting development in high-risk areas will require similar fortitude. 'Governments and states don't want to tell developers to not put things in a wetland, not put things in a floodplain,' he said. 'We should be telling people don't put them in a flatland, don't build in a way that your home is going to be more susceptible to wildfire.' Until then, hundreds of communities across the country could—and likely will—be the next Kerr County.