The latest on extreme weather in the US

Extreme temperatures can turn deadly, quickly in the United States, killing more than 700 people every year, according to the US Centers for Disease Control and Prevention.?Nearly one-third of the US population is under heat warnings or advisories on Tuesday with no sign of the above-normal temperatures letting up next week, according to the National Weather Service Climate Prediction Center.

While dehydration is a common concern, “the most worrisome consequence” of high heat is heat stroke, said Dr. Scott Dresden, an assistant professor of emergency medicine at Northwestern University. Heat stroke can cause confusion, seizures and even death, he said.

Humidity is one of the main things that can affect your body’s ability to cool itself off, according to the CDC.

“When the humidity is high, sweat won’t evaporate as quickly. This keeps your body from releasing heat as fast as it may need to,” the CDC says.

Personal factors can also play a role in very hot weather. These are things like “obesity, fever, dehydration, heart disease, mental illness, poor circulation, sunburn, and prescription drug and alcohol use,” the CDC says, adding that older people — specifically those 65 and older — are at high-risk for heat-related illness.

There are things you can do to stay safe, according to The Federal Emergency Management Agency’s Ready program.

First, be prepared:

During extreme heat, remember:

What to do if you see signs of heat stroke? Here’s advice from the CDC:

If you see any of these signs, you may be dealing with a life-threatening emergency — you should get medical attention as soon as possible, the CDC says. While waiting for first responders, try to cool the person down.

As of Tuesday morning, all visitors are out of Yellowstone National Park, Superintendent Cam Sholly said at a news conference. He said officials have also located all backcountry campers, with only one group left in the northern loop.

The Yellowstone River, which runs through the park and several Park County cities, swelled to a record high Monday due to recent heavy rainfall and significant runoff from melting snow in higher elevations, the park has reported.

Officials say the park will remain closed to visitors. The flooding has also prompted park evacuations and left some in surrounding communities trapped without safe drinking water.

The next step is to evaluate the infrastructure, but Sholly said there is not a firm timeline on when the park will be able to reopen.

When asked about the extent of the damage, he said, “We don’t know exactly yet,” adding that the northern loop was most affected by the flooding.

When the flood waters subside next week, Sholly said the park will pull together people from different agencies to assess and calculate how much time and money it will cost to rebuild. The superintendent said this is going to be a big job, estimating there are “hundreds” of bridges and major roads throughout the park that need to be evaluated.

Unprecedented flooding: The Yellowstone River reached record-high levels Monday in the Montana towns of Corwin Springs and Livingston.

At Corwin Springs, the river rose more than 5 feet on Monday morning, according to the National Oceanic and Atmospheric Administration river gauge data. The gauge reading was 13.85 feet on Monday afternoon, surpassing the historical high crest of 11.5 feet from 1918.

The river gauge reading at Livingston was a record 10.9 feet.

June precipitation has been more than 400% of average across northwestern Wyoming and southern Montana, according to CNN meteorologists.

CNN’s Claudia Dominguez and Sara Smart contributed to this reporting.

A Montana helicopter company has flown dozens of people in and out of the Gardiner community airstrip in Park County on Monday and Tuesday after the town located at the northern entrance to Yellowstone National Park was isolated by heavy flooding in the area.

Laura Jones with Rocky Mountain Rotors told CNN that the company’s aircraft has transported about 40 people.

She said they learned on Tuesday afternoon that the road from Gardiner to Livingston had opened and people had gotten out.

“We have had several flights we had booked tomorrow, and Thursday cancel now that they can get out,” she said.

Hundreds of thousands of customers continue to be without power today after severe storms impacted several states on Monday in the Midwest and the Ohio River Valley.?

On Tuesday, another round of severe weather is adding to the totals without power, this time in the Southeast.

All of these regions have now been under a heat advisory and/or excessive heat warning for a second day, with temperatures climbing into the upper 90’s and heat indices making it feel above 100 degrees.

Currently, there are 490,143 customers without power in at least seven states, according to data from PowerOutage.US.?

Ohio continues to experience the brunt of the outages at 310,324 customers in the dark.

Here’s a look at the outages:

Residents watch part of the Sheep Fire?wildfire?burn through a forest on a hillside near their homes in Wrightwood, California, on June 11.

There are currently 40 active large wildfires burning in the United States, according to a fire update from the National Interagency Fire Center (NIFC).

So far, the 40 large fires have burned approximately 1,192,672 acres in six states, the NIFC said.?

“Seven new large fires were reported yesterday, three in Alaska and Arizona and one in Utah. More than 6,200 wildland firefighters and support personnel are assigned to incidents,” according to the NIFC.?

The majority of the fires this year have been due to human-related causes.

Nearly 30,000 wildfires have burned around 2.5 million acres across the US so far this year — exceeding the pace of any year over the past decade, statistics released Tuesday by the?National Interagency Fire Center?show.

This makes 2022’s early wildfire season the largest in a decade, and the third-largest since records began in 1999 — behind a record 4 million acres in June in 2011, and 2.7 million acres burned in 2006, according to NIFC spokesperson Sheri Ascherfeld.

Alaska is currently experiencing the most active wildfires in the country.

In an update today from the Alaska Wildland Fire Information, it said the East Fork Fire has burned 129,197 acres and the Apoon Pass Fire has burned 43,820 acres.

These are the states currently reporting large fires, according to NIFC:

CNN’s Ella Nilsen and Brandon Miller contributed reporting to this post.

Floodwaters inundate property near the Clarks Fork Yellowstone River in between Edgar and Fromberg, Montana, on June 13.

Over three days, abundant rainfall and rapid snowmelt combined to produce up to three-quarters of a foot of water runoff, leading to the historic?flooding?across the region that spans Yellowstone National Park and the Montana and Wyoming border.

“The Beartooths and Absarokas received anywhere from 0.8 inches to over 5 inches of rainfall over the course of June 10th through June 13th,” the National?Weather?Service in Billings revealed Tuesday.

“This combined with anywhere from 2 to nearly 5 inches of?snow?melt equivalent, leading to a total water event of at least 4 to 9 inches,” they added. Snow?melt equivalent is the measurement of water created once the?snow?melts.

According to CNN?Weather?calculations, this amount of runoff is similar to the area receiving two to three months of June precipitation in only three days.

Though cooler temperatures and drier weather have allowed for the rivers to drop back to normal levels, even hotter temperatures are expected late this week and weekend, which could bring additional flooding to the region.

“Plan on highs in the 60 to 70s in the higher elevations [Friday and Saturday], which should melt much of the remaining snowpack and lead to additional river rises,” the NWS in Billings said on Tuesday.

This week’s extreme weather — severe flooding, dangerous heat and associated power outages — spans thousands of miles, but they are connected by one thing: a massive pattern of blocked weather over the US.

These “blocking systems” disrupt the normal movements of weather systems, and can keep heat trapped in one part of the country. Atmospheric blocking happens when the fluctuation of the jet stream — the narrow bands of powerful winds high in the sky that determine day-to-day weather around the globe — causes a traffic jam of sorts.

During the summer, these traffic jams can cause extreme and prolonged heat, also known as “heat domes.” This happened during the deadly heat wave that seared the Pacific Northwest last year, according to a?recent study?published in April.

Studies?have shown?that the climate crisis could affect the frequency of blocking, in concert with its geographic distribution. But?scientists say?one thing is certain: climate change is making heat waves warmer and severe storms such as hurricanes wetter than previously recorded.

The highway between Gardiner and Mammoth is shown in Gardiner, Montana, as historic flooding damages roads, bridges and homes on Monday, June 13.

The town of Gardiner in Park County, Montana, has been left isolated and surrounded by water after heavy flooding washed out bridges and roads, Park County officials said in a?post?on their Facebook page on Tuesday.

“Extensive flooding throughout Park County has washed out bridges, roads, and left communities and homes isolated,” the post said. “Gardiner is currently isolated and surrounded by water.”

Gardiner is located at the northern entrance to Yellowstone Park, according to its website.

“Gardiner is a center of activity for visitors to the region, serving as the only entrance into Yellowstone National Park that remains open to wheeled-vehicle use year-round,” according to the town’s website.

CNN tried to contact Park County officials, to confirm how many people are affected but has been unable to reach anyone.

The town is also urging visitors to be patient because after the flood waters recede “we could be looking at a significant loss to our tourism based economy,” Gardiner’s tourist information center said in a Facebook post.

The flooding has caused many roads and bridges to be inaccessible. Some railroad tracks have had to shut down because water have crossed the tracks, the post said adding that the “majority of bridges crossing the Yellowstone River in the Paradise Valley are not safe for use. Exceptions are Pine Creek, Murphy Lane and Mill Creek, but they are available for emergency traffic only.“

An aerial view of Yellowstone National Park's flooded out North Entrance Road in Gardiner, Montana, on June 13.

The Yellowstone River runs through the town of Gardiner.

“Personnel from agencies across the region and state are assisting local resources on the response. There are evacuations and rescues going on throughout the county, including two air lifts (up the Boulder and near Cooke City-Silver Gate) and several swift water rescues,” the post added.

“Two Bear Air and the National Guard have been assisting with the air rescues while Park County Search is assisting with the swift water rescue,” the post said, adding that rescue personnel has been brought in to deal with “potential need.”?

Officials warned residents that displaced wildlife could traverse their properties and that bears, deer and domestic livestock have been spotted.??

The flooding, officials say, “has also made drinking water unsafe in many areas” and the Montana Department of Environmental Quality issued a no drink order in the area after a water main broke.

Officials also said that once waters recede bridges and roads will be assessed to verify if they are structurally sound.

See video of the devastation in Gardiner here.

The Tennessee Valley Authority is seeing a record demand for power demand this month, according to a company tweet Tuesday.

Summer classes and programs in the Milwaukee Public School district were dismissed early Tuesday for the second day in a row due to intense heat.

Schools and Summer Academy sites were dismissed after lunch after the local health department?declared a two-day Heat Health Advisory.

At 2 p.m. local time, the National Weather Service registered the heat index at 108 degrees Fahrenheit at Mitchell International Airport in Milwaukee.

The heat will stick around next week for much of the US, according to the National Weather Service Climate Prediction Center.

More than 100 million people are under heat warnings or advisories on Tuesday, spanning from Minnesota to the Florida Panhandle.

In its eight to 14 day outlook, the Climate Prediction Center shows many southern states are expected to experience “above normal” temperatures for the week of June 21-27. The highest probability is in Alabama, Mississippi and parts of Louisiana, Arkansas and Texas.

Some of those “above normal” temperatures could get dangerous. There is a high risk for excessive heat in that southeast region for June 21-23, the Climate Prediction Center said, adding there is a slight and moderate risk for high temperatures in much of the rest of the US.

Even as the Midwest and Southeast endure dangerous heat and humidity and the Yellowstone National Park area deals with flooding, we shouldn’t take our eyes off the risk for more wildfires today in the Southwest, Rockies and northern Great Plains.

Because of hot, dry and windy conditions, northeastern New Mexico and south-central Colorado have a critical — or level 2 of 3 — threat of fire today, the Storm Prediction Center says. That area includes New Mexico’s Calf Canyon/Hermits Peak Fire, which has burned more than 325,000 acres since April and is only 70% contained.

A lower fire threat — “elevated,” or the first of three levels — exists for a wider portion of the country, including parts of Arizona, Utah, Wyoming, Nebraska and South Dakota, according to the prediction center.

Included in that is the Flagstaff, Arizona, area, where high winds continue to exacerbate the Pipeline and Haywire fires. The Pipeline Fire alone has forced evacuation orders for hundreds of homes, and has scorched thousands of acres since it started Sunday.

The sense of urgency around a deadly heat wave never seems to match that of a hurricane making a landfall or a wildfire destroying a town.

That’s because heat is a “silent killer,” said Kristie Ebi, a climate and health researcher at the University of Washington.

A heat dome last year scorched the Pacific Northwest for several days in a row in June, leading to hundreds of deaths in British Columbia, Washington and Oregon. Officials called it a “mass casualty event,” and scientists concluded it would have been?“virtually impossible” were it not for the climate crisis.

“We’ve all experienced hot summers — and we got through it, in our memories, just fine,” Ebi said. “And we may not have been aware that some of our neighbors suffered during that event, so heat is a challenge that does affect all of us, particularly the most vulnerable.”

Much like the pandemic, extreme heat also disproportionately kills low-income communities, people of color and the elderly populations. A?2020 analysis?found that the number of heat-related deaths in the US each year has been underestimated since records typically only look at medical terms such as heat stroke, and neglects other potentially heat-related causes of death, like heart attacks and other underlying conditions.

“People are generally unaware and don’t think about the risks associated with these high temperatures,” Ebi said.

She added that it’s important to understand that the climate is not like what it was even just a few years ago. The climate crisis is already affecting our lives today, and it will continue to hit the most vulnerable.

“We all look forward to the summer as we enjoy the warmer temperatures, but there are people who are at risk at higher temperatures,” she said. “As the climate continues to change or higher temperatures get higher than what we experienced when we were younger, people need to pay more attention, particularly to those around you.”

Part of a highway is washed away near Gardiner, Montana, on June 13.

Montana Gov. Greg Gianforte declared a “statewide disaster” on Tuesday due to heavy flooding, according to a?post on his Twitter account.?

Montana is experiencing unprecedented levels of flooding according to the National Weather Service. Snow melt and rainfall across the Beartooths and Absarokas, that span the Montana-Wyoming border according to the US Forest Service, have led to “flooding rarely or never seen before across many area rivers and streams,” the NWS Billings on their website.?

Gianforte also said in a separate tweet that the Montana National Guard had “successfully evacuated 12 individuals stranded due to flooding in Roscoe and Cooke City.”?

The Montana National Guard said that after rescuing those 12 stranded individuals they were responding to a search and rescue request in the East Rosebud Lake area according to a?tweet.?

Montana’s Disaster and Emergency Services warned in a?tweet on Tuesday that “several roads and bridges are severely damaged in Southern Montana and may be temporarily closed.”?

?See the governor’s tweet:

Wind turbines rotate in a field in Eldorado, Texas.

As an unusually early heat wave blankets Texas, many people are turning on their air conditioners — setting new records for electricity demand in the state. On Sunday, electricity demand surpassed 75 gigawatts, smashing a 2019 record. And Texas grid operator ERCOT projects Tuesday could near the same peak.?

But compared to past Texas grid failures during extreme weather, what’s notable this time is how well the grid is working during the power surge. Several experts told CNN that it’s owed in large part to strong performances from wind and solar, which generated 27 gigawatts of electricity during Sunday’s peak demand — close to 40% of the total needed.

Despite Texas Republican state politicians’ rhetoric hitting wind and solar as being unreliable, Texas has a massive and growing fleet of renewables. Zero-carbon electricity sources (wind, solar, and nuclear) powered about 38% of the state’s power in 2021, rivaling natural gas at 42%.

In Texas, this is a relatively recent phenomenon.

“Wind and solar would not have been available in years in the past, so the growing capacity helps to alleviate reliance on natural gas and coal,” said Jonathan DeVilbiss, operations research analyst at the US Energy Information Administration.

Not only have renewables helped keep the power on during a scorching and early heatwave, they have also helped keep costs low. Prices for natural gas and coal have remained higher during the worldwide energy crunch; unlike fossil fuels, renewables have zero fuel costs.

“Because the price of wind and sunlight hasn’t doubled in the past year like other resources, they are acting as a hedge against high fuel prices,” said Joshua Rhodes, an energy researcher at UT Austin.

Keep reading here.

Correction: This post has been updated to correct Joshua Rhodes’ name.

Severe storms on Monday knocked out power to hundreds of thousands of homes and businesses in the Midwest and the Ohio River Valley – including those in and around Chicago. And the satellite imagery above gives a pretty stunning view of the storm that hit the Windy City.

It was tweeted by the Cooperative Institute for Research in the Atmosphere, a partnership between the Colorado State University and the National Oceanic and Atmospheric Administration.

More than 525,000 homes and businesses still were without power late Tuesday morning in six states — Ohio, West Virginia, Indiana, Illinois, Michigan and Wisconsin. More than 299,000 were in Ohio alone, according to PowerOutage.us.

Illinois still had more than 36,000 outages late Tuesday morning, most of which were in Cook County, which contains Chicago.

A family spends time together in the shade outside of their house in Houston, Texas, in this June 10, 2022.

Heatwaves are something we are going to have to get used to.

“Climate change is increasing the frequency and intensity of heat waves around the world, tilting the scale in the direction of warmer temperatures,” CNN meteorologist and climate expert Brandon Miller explained.

“In the United States, record high temperatures are now well more than twice as likely to occur compared to record low temperatures,” according to the US National Climate Assessment.

In Europe, heat is being pumped north around an area of high pressure, similar to what we have going in the US. It is bringing unrelenting heat to Spain and France through the rest of the week.

In France, it is likely to peak Thursday and Friday. Spain, where it will last until at least Thursday, is also dealing with an astonishing drought. The aridness, coupled with the heat, is putting most of the country into “extreme” fire danger.

It is very similar to what is happening in New Mexico, where the fire threat is critical once again, today and tomorrow.

And then there is northwestern China, where temperatures will reach well into the triple digits Fahrenheit.

High water levels in the Lamar River erode the Northeast Entrance Road to Yellowstone National Park.

The flooding in and around Yellowstone National Park is indicative of the extremes of the climate crisis, Marshall Shepherd, the director of the Atmospheric Sciences Program at the University of Georgia, told CNN.

“We have warned about increasing rates of (rainfall) intensity,” Shepherd said. “Our infrastructure is unfortunately designed for last century rain intensities.”

As for the heat, Shepherd said extreme temperatures never get the same urgency in headlines as something like a hurricane, but they kill more people each year.

“The hot ‘night’ temperatures, coupled with the urban heat island, are particularly dangerous for vulnerable communities,” Shepherd said.

Heat islands are urban areas that experience higher temperatures than surrounding areas because of their high concentration of pavement, buildings and other built infrastructure – which intensify heat – and the lack of natural green spaces, which have a cooling effect.

Communities trapped in these urban heat islands, which tend also to be the poorest, are enduring the greatest burdens of our rapidly warming planet.

The flooding in southern Montana and northern Wyoming has washed away parts of roads and homes and other structures — including a building along the swollen Yellowstone River in Gardiner, Montana.

The video below, compiled from footage from several people, shows the structure collapsing Monday into the swiftly moving river.

The Yellowstone River, which runs through several Montana communities including Gardiner, swelled to a record high Monday due to recent heavy rainfall and significant runoff from melting snow in higher elevations, according to CNN meteorologist Brandon Miller.

Flooding in the region also forced officials to close Yellowstone National Park to visitors through at least Wednesday.

Watch the video:

A firefighter watches a helicopter drop water on the Sheep Fire in Wrightwood, California, on Sunday, June 12.

Nearly 30,000 wildfires have burned around 2.5 million acres across the US so far this year — exceeding the pace of any year over the past decade, statistics released Tuesday by the National Interagency Fire Center show.

This makes 2022’s early wildfire season the largest in a decade, and the third-largest since records began in 1999 – behind a record 4 million acres in June in 2011, and 2.7 million acres burned in 2006, according to NIFC spokesperson Sheri Ascherfeld.

Ascherfeld said that climate change is compounding the challenges of fighting wildfires.

Wildfires are now happening in different parts of the country, burning more land on average each year, and becoming more extreme, Ascherfeld added.

President Joe Biden traveled to wildfire-devastated New Mexico last weekend, where crews are still battling the largest and second-largest fires on record in the state.

This weekend saw new, large wildfires start in California and Arizona. The Pipeline Fire north of Flagstaff, Arizona, has now grown to 5,000 acres and resulted in hundreds of evacuations.

A?heat dome?that began last week in the Southwest has shifted east — so areas from the Upper Midwest to the Southeast are set to get hit today with potentially dangerous combinations of heat and humidity.

More than 100 million people — nearly a third of the US population — are under either excessive heat warnings or heat advisories from roughly Minnesota to the Florida Panhandle.

High temperatures could hit 100 degrees or above in cities including St. Louis; Charlotte; and Columbia, South Carolina, the National Weather Service says. But in many more places from the Midwest to the Southeast, humidity will put the heat index — what the air feels like — above 100 degrees. As the Weather Prediction Center said Tuesday:

The map above also shows an excessive heat warning for parts of Arizona and Southern California. Those are early warnings that take effect Thursday, when high heat returns to the Southwest.

Here, by the way, is a chart showing how you’d calculate the heat index if you knew the temperature and the relative humidity:

Heat?already kills?more Americans than any other weather-related disaster, according to the National Weather Service — and climate change is making these extreme events even more dangerous.

The Northwest’s record-breaking heat wave in June, which scientists say would have been “virtually impossible” without human-caused climate change, for instance,?killed hundreds?of people in Oregon, Washington and British Columbia. When Hurricane Ida pummeled Louisiana early this month, a heat wave?exacerbated the impacts of the storm.

The compounding consequences of extreme heat don’t fall equally across communities. A?recent study?from the University of California, San Diego, found that low-income neighborhoods and communities with high Black, Hispanic and Asian populations experience significantly more heat than wealthier and predominantly White neighborhoods.

It reflects an?earlier study?that traces the legacy of neighborhood?redlining, the government-sanctioned effort in the 1930s to segregate people of color by denying them housing loans and insurance. While redlining was banned in the late 1960s, remnants of the discriminatory practice are still apparent.

The research analyzed 108 cities in the United States and found that 94% of historically redlined neighborhoods are disproportionately hotter than other areas in the same city.

Redlined neighborhoods typically suffer the most from the?urban heat island effect, according to the study, in which some urban areas can be up to 20 degrees hotter than neighborhoods just a few blocks away. Areas with a lot of asphalt, buildings and freeways absorb more of the sun’s heat than areas with parks, rivers and tree-lined streets.

Vivek Shandas, lead author of the redlining study and professor of climate adaptation and urban policy at Portland State University, said in addition to historic planning policies, the materials used to construct buildings also play a huge role in amplifying the most severe effects of extreme heat, particularly in low-income apartment complexes.

“What we end up seeing, as these higher density buildings are made of materials that are often able to withstand a heavier load from the multiple floors, is that they’re made out of concrete and steel, which amplifies heat,” Shandas previously told CNN. “So not only do we have historic planning policies that are creating a distribution of heat that’s inequitable, we’re also seeing the kinds of buildings that are going into historically disinvested neighborhoods are those types of buildings that retain the sun’s solar radiation, and then amplify it.”

The effect is striking on the walk from Manhattan’s Central Park to East Harlem, says Sonal Jessel, director of policy at the Harlem-based nonprofit WE ACT for Environmental Justice.

The trees that dot the wealthy and predominantly white Upper East Side neighborhood begin to disappear, Jessel says. In contrast, East Harlem, a diverse and historically marginalized neighborhood, is surrounded by freeways and streets, has less tree cover and more industry.

Portland, Oregon, and Seattle, two major cities that got scorched by the June heat wave, rank first and third, respectively, among cities with the highest proportion of households without air conditioning, according to a?US Census Bureau survey?of 25 major metropolitan areas.?Experts say?those least likely to have air conditioning are the people who will endure the worst heat – historically underserved communities.

“And unfortunately, we’re not well prepared, just generally speaking in the Pacific Northwest, for heat,” Shandas said. “That’s where the human side of it comes up, whether people are recognizing that they’re actually experiencing some level of heat stress and it might be an unfamiliar experience for them.”

CNN’s Dr. Sanjay Gupta contributed reporting to this post.

Read the full report here.

Transmission towers are seen at the CenterPoint Energy power plant on Thursday, June 9, in Houston, Texas. Power demand in Texas is expected to set new all-time highs as heat waves surge to levels rarely seen outside of summer, and economic growth contributes to higher usage in homes and businesses. The Electric Reliability Council of Texas (ERCOT) has said that it has enough resources to meet demand.

As heat ramps up ahead of what forecasters say will be a?hotter than normal summer, electricity experts and officials are warning that states?may not have enough power?to meet demand in the coming months. And many of the nation’s grid operators are also not taking climate change into account in their planning, even as extreme weather becomes more frequent and more severe.

All of this suggests that more power outages are on the way, not only this summer but in the coming years as well.

Power operators in the Central US, in their?summer readiness report, have already predicted “insufficient firm resources to cover summer peak forecasts.” That assessment accounted for historical weather and the latest NOAA outlook that projects for more extreme weather this summer.

But energy experts tell CNN that some power grid operators are not considering how the climate crisis is changing our weather — including more frequent extreme events — and?that is a problem?if the intent is to build a reliable power grid.

Webb said many power grid operators use historical weather to make investment decisions, rather than the more dire climate projections, simply because they want to avoid the possibility of financial loss for investing in what might happen versus what has already happened. She said it’s the wrong approach and it makes the grid vulnerable.

“We have seen a reluctance on the part of many utilities to factor climate change into their planning processes because they say the science around climate change is too uncertain,” Webb said. “The reality is we know climate change is happening, we know the impact it has in terms of more severe heatwaves, hurricanes, drought, and we know that all of those things affect the electricity system so ignoring those impacts just makes the problems worse.”

An early heatwave?knocked six power plants offline in Texas?earlier this month. Residents were asked to limit electricity use, keeping thermostats at 78 degrees or higher and avoid using large appliances at peak times. The Electric Reliability Council of Texas, or ERCOT, in its seasonal reliability report, said the state’s power grid is prepared for the summer and has “sufficient” power for “normal” summer conditions, based on average weather from 2006 to 2020.

But NOAA’s recently released?summer outlook?forecasts above average temperatures for every county in the nation.

“We are continuing to design and site facilities based on historical weather patterns that we know in the age of climate change are not a good proxy for future conditions,” Webb told CNN.

When asked if the agency is creating a blind spot for itself by not accounting for extreme weather predictions, an ERCOT spokesperson told CNN the report “uses a scenario approach to illustrate a range of resource adequacy outcomes based on extreme system conditions, including some extreme weather scenarios.”

The North American Electric Reliability Corporation, or NERC — a regulating authority that oversees the health of the nation’s electrical infrastructure — has a less optimistic projection.

In a recent seasonal reliability report, NERC placed Texas at “elevated risk” for blackouts this summer. It also reported that while much of the nation will have adequate electricity this summer, several markets are at risk of energy emergencies.

California grid operators in its summer reliability report also based its readiness analysis on “the most recent 20 years of historical weather data.” The report also notes the assessment “does not fully reflect more extreme climate induced load and supply uncertainties.”

Compounding the US power grid’s supply and demand problem is?drought: NERC tells CNN there’s been a 2% loss of reliable hydropower from the nation’s?power-producing dams. Add to that the rapid retirement of many coal power plants — all while nearly everything from toothbrushes to cars are now electrified. Energy experts say adding more renewables into the mix will have the dual impact of cutting climate change inducing greenhouse gas emissions but also increasing the nation’s power supply.

Read the full report here.

The reason behind the extremely high temperatures is an area of high pressure creating a clear lid over the Western US. The lid will trap any escaping radiation and send it back to the ground, while the sun’s rays continue to penetrate through.

It’s called a?heat dome, and here’s how it forms:

This?heat dome?began last week in the Southwest and slowly shifted over to the eastern US, where heat and humidity are climbing together to levels that will significantly?impact the human body.

Learn more about heat domes in this video here.

More than 500,000 utility customers who are currently without power because of yesterday’s severe weather in the Midwest and the Ohio River Valley are also under excessive heat warnings or heat advisories for today, according to analysis from CNN Weather using power outage numbers from PowerOutage.us.

Nearly 300,000 of them are in Ohio, with the rest being in Illinois, Indiana, Michigan and West Virginia. Key cities impacted include Cincinnati, Chicago and Fort Wayne, Indiana.

Locations in the heat alert areas will see dangerous heat indices between 100 and 110 degrees this afternoon, which can turn deadly for those without access to air conditioning.

Daily high temperature records were set across several cities Monday afternoon. Here are a few:

Severe storms that moved across the Upper Midwest and the Ohio River Valley left more than 620,000 customers without power early Tuesday, according to?PowerOutage.us, with more than 370,000 outages in Ohio alone.

Thunderstorms prompted a tornado warning in Chicago during the busy evening rush hour as wind gusts of up to 84 mph buffeted the city.

The same storm system brought lashing winds and rain to portions of western Ohio, Michigan and northern Indiana, generating more than 200 wind reports in the region, including a 98 mph gust in Fort Wayne, Indiana.

A heat dome that enveloped the Southwest in heat and humidity last week shifted to the central US and put more than 125 million people in the region under heat advisories.

That’s more than one third of the US population enduring potentially dangerous heat levels.

Several cities set temperature records Monday afternoon, including Asheville, North Carolina, St. Louis and Nashville. In North Platte, Nebraska, the temperature rocketed to a record 108 degrees.

The heat will continue to travel northeast into the upper Mississippi Valley, western Great Lakes and Ohio Valley, and it will continue to build Tuesday over the southern Mid-Atlantic and Southeast, according to the Weather Prediction Center.

More than 100 million people are under some sort of heat alert Tuesday.

Excessive heat forecasts forced some schools in Michigan, Minnesota and Wisconsin to announce that classes will be canceled, close early or move online this week.

Even after this heat dome subsides, relief could be short-lived. Heat waves will become increasingly common and more severe, experts say.

“In the United States, record high temperatures are now well more than twice as likely to occur compared to record low temperatures,” according to the US National Climate Assessment.

Yellowstone National Park will?remain closed to visitors?through at least Wednesday due to dangerous flooding conditions, which have prompted park evacuations and left some in surrounding communities trapped without safe drinking water, officials announced Monday afternoon.

“Our first priority has been to evacuate the northern section of the park where we have multiple road and bridge failures, mudslides and other issues,” Yellowstone Superintendent Cam Sholly said in a statement Monday.

A road in Yellowstone National Park partially collapsed due to flooding Monday.

The Yellowstone River, which runs through the park and several Park County cities, swelled to a record high Monday due to recent heavy rainfall and significant runoff from melting snow in higher elevations, according to CNN meteorologist Brandon Miller.

The Yellowstone River gauge at Corwin Springs, Montana, reached 13.88 feet Monday afternoon, surpassing the historical high crest of 11.5 feet from 1918,?NOAA river gauge data?shows. “The river is still rising near Livingston, and it is expected to crest between 6 p.m. and 9 p.m. on Monday,” Park County officials said on Facebook.

Some are evacuated while others remain trapped

As several roads and bridges are rendered impassable by floodwaters, park and county officials are working to evacuate whoever they can and provide support to those who are unable to leave.

The Park County Sheriff’s Department issued a shelter in place order until 7 a.m. Monday for those south of mile marker 52.5 on US Highway 89 South, the Facebook post said.

The National Guard and local search and rescue teams were assisting with evacuations and rescues throughout the county, including two air lifts and one swift water rescue, the county said.

Multiple communities in Park County are isolated and surrounded by water, including Gardiner, Cooke City and Silver Gate, an update?on the county Facebook page?said. Quickly rushing floodwaters have also damaged homes, as images show houses either partially or fully collapsing.

In neighboring Carbon County, Montana, flooding compromised utility service lines, leaving many customers in Red Lodge without power, officials said.

Meanwhile, several roads and bridges in Yellowstone have also been compromised by flooding, park officials say. Videos released by the park show portions of paved road washed out or severely eroded.

CNN’s Sara Smart, Claudia Dominguez, Raja Razek, Brandon Miller and Amanda Jackson contributed to this report.

Read the full report here.