People in much of the U.S. checked their phones on June 13 to find a severe weather alert of some kind, and in some places, multiple alerts at different times of the day.
Floodwaters caught on camera ravaged Yellowstone National Park, decimating roads and forcing officials to close the park to visitors. Videos taken in other parts of the country on June 13 or the days leading up to it show heavy rain and wind from a nighttime derecho, which is a widespread wind and thunder storm, and plumes of smoke from a massive wildfire along a desert horizon.
One person on Twitter reshared a video of Yellowstone’s flooding and claimed there were at least six natural disasters across the U.S. in a single evening in a tweet liked more than 40,000 times. Other people discussing the original tweet repeated that six “extreme weather events” occurred in a single day: June 13.
Were there six extreme weather events in the U.S. in a single day?
Yes, there were six extreme weather events in the U.S. in a single day.
WHAT WE FOUND
People in different parts of the U.S. experienced heat, storms, wildfires and droughts on June 13. A little less than a third of the U.S. population was subjected to an intense heat wave in the Midwest and South for the whole day, a derecho swept through the Midwest and down into the South after nightfall, a record-breaking flood closed down Yellowstone National Park, wildfires burned in Alaska and the arid Southwest, while an extreme drought remained in effect across the West.
Each of these weather events were serious enough to be classified as dangerous or hazardous by the standards of the Federal Emergency Management Agency (FEMA)’s National Risk Index. Natural phenomena that meet FEMA’s natural hazard criteria have the potential to create natural disasters, which are determined based on their human impact.
On the evening of June 13, a type of wind and thunder storm known as a derecho swept across parts of the Midwest, Appalachian Mountains and Southeast. According to the National Weather Service, three rounds of severe storms began that afternoon and created a significant swath of straight-line wind damage as they continued into the overnight hours.
The National Oceanic and Atmospheric Administration (NOAA) says a derecho can produce destruction similar to that of a tornado, but the damage typically occurs in one direction along a relatively straight path — hence “straight-line wind damage.” The storm must be long-lived, continually creating wind damage for at least 400 miles, and consistently produce wind gusts of at least 58 mph while it wreaks havoc.
According to the National Weather Service (NWS), a wind gust of 98 mph from the derecho was recorded at the Fort Wayne International Airport, breaking a previous record. Other wind measurements in the Fort Wayne, Indiana, area ranged from 50 to 75 mph and led to significant damage.
Heat Wave Across Central and Eastern U.S.
On June 13, people across the Midwest, the Great Plains and the Southeast faced triple-digit temperatures and heat indexes, which are a measure of what the temperature feels like because of the humidity. The heat indexes in these areas reached as high as 110 or even 120 in spots. At least two deaths in Wisconsin are being investigated as potential heat-related deaths.
FEMA defines a hazardous heat wave as “a period of abnormally and uncomfortably hot and unusually humid weather typically lasting two or more days with temperatures outside the historical averages for a given area.”
Although that definition doesn’t include specific numbers, FEMA uses NWS weather alerts for determining a region’s risk for experiencing heat waves. The most urgent heat alert the NWS issues is an excessive heat warning.
“[An excessive heat warning is] when the maximum heat index temperature is expected to be 105 degrees or higher for at least 2 days and night time air temperatures will not drop below 75 degrees; however, these criteria vary across the country, especially for areas not used to extreme heat conditions,” the NWS says. “If you don't take precautions immediately when conditions are extreme, you may become seriously ill or even die.”
On June 13, the NWS Weather Prediction Center reported that excessive heat warnings, watches and advisories were in effect for about a third of the country’s population due to record-breaking temperatures.
“Heat index values exceeded 105 degrees starting on June 12 and continued through June 16,” said the NWS Paducah, Kentucky, office. “The most oppressive day was June 13, when dewpoints in the mid 70s to around 80 produced heat index values of 110 to nearly 120.”
In Montana, the NWS Billings office said a combination of heavy rain and significant snowmelt between June 10 and June 13 caused “unprecedented” flooding in South-Central Montana — most notoriously in Yellowstone National Park.
“This led to flooding rarely or never seen before across many area rivers and streams,” the NWS said.
The National Park Service (NPS) confirmed the flooding severely damaged infrastructure in Yellowstone National Park. The NPS reported all entrances to Yellowstone National Park remained closed as of June 14, its most recent update at the time of publishing.
Photos and videos posted by the NPS show the floodwaters have completely washed away the ground beneath roads and destroyed bridges across the park. Entire chunks of riverside road in Yellowstone have been destroyed as a result.
Montana Governor Greg Gianforte declared a statewide disaster in response to the flooding.
Western U.S. Drought
Although its visuals aren’t nearly as dramatic as the Yellowstone flooding, droughts can be perilous and have plagued most of the western U.S. for well over a year. The dry conditions have slowly dried up the region’s lakes and created water shortages in the area.
FEMA defines a hazardous drought as a “deficiency of precipitation over an extended period of time resulting in a water shortage.” It uses the U.S. Drought Monitor, which is operated by the University of Nebraska-Lincoln's National Drought Mitigation Center, to determine drought risk across the U.S.
As of June 14, 78% of the Drought Monitor’s West region was in at least moderate drought conditions, including 12% of which was in an exceptional drought — the driest rating on its scale. This drought has been ongoing for well over a year — the last time the total drought area dropped below 78% was in April 13, 2021.
Since the start of 2021, between 40% and 60% of the continental U.S. has consistently experienced moderate drought conditions or worse. The effects of this severe drought can be seen in the region’s major lakes: Great Salt Lake and Lake Mead. The Great Salt Lake is no larger than 44% of its normal surface area, and Lake Mead, which helps supply water to 40 million people across seven states and northern Mexico, is at 35% of its capacity.
Western U.S. Wildfires
Large fires have blazed in Santa Fe National Forest and Gila National Forest in New Mexico since May, and another large fire recently sparked in Arizona’s Coconino National Forest. Multiple large cities — namely Santa Fe, New Mexico, and Flagstaff, Arizona — are just a stone’s throw from a wildfire.
FEMA says wildfire is an “unplanned fire burning in natural or wildland areas such as forests, shrub lands, grasslands, or prairies.”
The National Interagency Fire Center (NIFC) says that five states — Alaska, Arizona, California, New Mexico and Texas — are currently reporting large wildfires.
The largest two wildfires in the continental U.S. right now are both in New Mexico, and both of them began in May. New Mexico is the state most affected by exceptional drought right now — 52% of the state is experiencing the driest conditions possible. The third-largest fire in the continental U.S. is in Arizona, and started on the morning of June 12.
More acres of Alaskan wilderness are currently burning than in every other state combined, according to NIFC.
NIFC says that wildfires have burned more than 900,000 acres of land in Alaska. According to NASA, that’s already more than the 30-year median of 600,000 acres burned during the entire wildfire season. Typically over the past 30 years, 50,000 acres of Alaskan land has been burned by wildfires by mid-June.
What is a natural disaster?
FEMA, the International Federation of Red Cross and Red Crescent Societies (IFRC) and the U.S. Department of Homeland Security (DHS) all define “natural disasters” based on a natural catastrophe’s human impact.
FEMA says a disaster has to result in severe property damage, deaths and/or multiple injuries. IFRC says a disaster should cause “serious disruptions” to a community’s functioning that exceed the community’s “capacity to cope using its own resources.” DHS says a natural disaster should “pose a significant threat to human health and safety, property, critical infrastructure and homeland security.”
Although the President can use the Stafford Act to officially consider a catastrophe as a “major disaster” or “emergency declaration,” this designation only determines federal response. Once the President classifies something as a major disaster, the federal government and FEMA can use certain funding to support communities in various ways.
Currently, the Biden Administration has declared major disasters or emergency disaster declarations for the fires in the Southwest, most notably the massive New Mexico fires, and for the Yellowstone flooding. But an extreme weather event doesn’t have to be a “major disaster” to be considered a disaster by FEMA, and some disasters aren’t declared until months after the catastrophe occurred.
The extreme weather events that occurred on June 13 are in line with NOAA’s expectations of the ongoing and increasingly worsening effects of climate change.
“Incidents of extreme weather are projected to increase as a result of climate change,” NOAA says. “Many locations will see a substantial increase in the number of heat waves they experience per year and a likely decrease in episodes of severe cold. Precipitation events are expected to become less frequent but more intense in many areas, and droughts will be more frequent and severe in areas where average precipitation is projected to decrease.”