It is halfway through August and this year's Danger Season, the period between May and October when climate change makes summers extremely hot and brings more intense hurricanes, heat waves, flooding, and wildfires. Just this past week, the US was hit with record heat, wildfires, and a hurricane, with 2024 already ranking second for the number of billion-dollar disasters recorded.

In our Danger Season tracker, we are keeping tabs on how many people in the US, Puerto Rico, and the US Virgin Islands have been under heat, storm, flooding, or fire weather alerts issued by the National Weather Service.

Danger Season got a quick jump start early this year. By May 7, nearly one-third of the population had been under at least one alert, a number that jumped to half the population (nearly 170 million persons) by May 20. Extreme weather alerts continued to spread quickly throughout the US. On June 2, 75% (three-quarters) of all people in the country had faced at least one alert, and by June 22 that number reached 95%.

As of August 13, nearly everyone in the US has faced an extreme weather alert, and we still have most of August, as well as September and October to go. Only 79 counties and municipios (the county equivalent in Puerto Rico) throughout the country representing about 1% of the country's population and located mostly in Michigan, Minnesota, Alaska, and Wisconsin have not faced an alert as of August 13.

Who are most vulnerable and most impacted?

In 2022, we reported that counties with at least 21 heat alerts (amounting to nearly three weeks' worth of heat alerts though not necessarily in a row) were mostly in a handful of states in the Midwest and South. In these communities, poverty levels tend to be higher than the national average, and many communities lack the economic means to protect themselves during extremely hot weather and any other type of extreme weather.

To determine which populations may be more vulnerable to the extreme climate impacts that occur during Danger Season, I relied on the White House's Climate Justice and Economic Screening Tool (CEJST). CEJST does not include race or ethnicity, instead classifying communities as "disadvantaged" if they meet at least one of multiple categories of climate and economic burdens such as expected losses from flooding, as well as disparities related to energy, health, housing, and transportation. Though it omits race and ethnicity, the tool's results confirm what environmental justice advocates have said for a long time-that race is the strongest predictor of climate and pollution burdens.

In 2024, many counties that have at least 25% or more of their communities deemed disadvantaged also had at least 21 days of extreme heat alerts so far this Danger Season. And many of these counties have large metro areas where lots of Latinos, African Americans, and other people of color live. And on August 2,Climate Central's Climate Shift Index reminded us how much climate change is responsible for the brutal heat, as nearly half of the US population was under heat alerts that were three times as likely to exist due to climate change.

Many disadvantaged communities across the Pacific Northwest, the Southwest and parts of the Great Plains and the South have faced multiple extreme heat alerts between May 1 and August 13 of 2024.

Not just heat, but atmospheric conditions that lead to wildfires prevailed in the Southwest and Pacific Northwest. Fire weather alerts are issued by the National Weather Service when the atmospheric conditions that make wildfires more likely are ripe, such as low humidity, temperatures above 75⁰F, and wind speed in excess of 15 miles per hour. And similar to heat alerts, most places with a high total number of fire weather alerts (I picked 14 in this case, or two weeks' worth of alerts-again, not necessarily consecutive) are also home to many disadvantaged communities. Indeed, in July, large wildfires broke out across these regions and forced thousands to evacuate. These fires destroy people's homes and other property, and their risks and costs keep climbing.

Many disadvantaged communities across the Pacific Northwest and the Southwest have faced multiple extreme fire weather alerts between May 1 and August 13 of 2024.

As I write this, rain has been pouring almost uninterruptedly in Washington, DC and the surrounding suburbs where I live, as Tropical Storm Debby makes its way northeast. It's much worse in South Carolina, where people faced record rainfall, extensive flooding, and tornadoes. Unfortunately, it's not the first time this year that a storm has pummeled communities. In late April and the first days of May, eastern and southeastern Texas was flooded with heavy rains. Then Hurricane Beryl, after a long tour that began early in the southeast part of the Atlantic, ran roughshod across Houston and other nearby parts of Texas, knocking out power for 2.7 million folks across the state and costing upwards of one billion dollars in grid repairs. The map below captures areas that have had at least 7 flood alerts so far this Danger Season.

Many disadvantaged communities across coastal and inland areas faced multiple flood weather alerts between May 1 and August 13 of 2024.

During Danger Season, many of these impacts occur simultaneously. Just on August 9 alone, millions of people were under heat flood alerts from most of Texas through the South and Southeast and under flood alerts in most of the Eastern Seaboard. And some counties such as Florida were under both types of alerts on the same day.

Danger Season alerts on Friday, August 9, 2024. Heat alerts in yellow cover a large swath including the Southwest and Southeastern US, while flood alerts (in green) show widespread threats from Tropical Storm Debby across the Eastern Seaboard. Blue counties in Florida indicate where heat and flood alerts were issued on the same day.

What could be in store for the rest of the 2024 Danger Season?

August through September are peak hurricane season in the Atlantic Ocean and the Caribbean Sea. NOAA just revised down their May hurricane season forecast slightly, but it still expects an above-normal season with 8 to 13 hurricanes (and 4 to 7 of these predicted to be Category 3 or higher), a worrisome number of potentially catastrophic events. At the moment, Tropical Storm Ernesto has prompted a tropical storm watch for Puerto Rico and a hurricane watch for the US Virgin Islands and the islands Vieques and Culebra, two inhabited islands that are part of the Puerto Rican archipelago.

In terms of wildfires, the National Interagency Fire Center's outlook for August through October-a time that is often the height of the wildfire season-shows significant potential for wildfires in the Pacific Northwest and parts of the Southwest. And we are not out of the hot season yet-the National Weather Service's Heat Risk tool is forecasting moderate or worse heat-related impacts mostly in some parts of the Southern United States for this week, and it's too early to tell with certainty what temperatures will look like before the end of Danger Season in October.

We need immediate and sustained action

Climate change is fueling this new dangerous regime of extreme weather. Our government and industries need a sustained and steep downward path to reduce heat-trapping emissions, and we also need continuous resources and additional measures such as investments to protect people from the Danger Season impacts that are happening now. In addition, our own UCS experts have recommendations across these climate impacts from how to redress injustices brought on by hurricanes and heat in coastal regions, to protecting people and property from climate-fueled wildfires, as well as the critical infrastructure on which we rely to conduct our daily lives.

Public link

Please use the above public link if you want to share this noodl on another website.