Phoenix’s Extreme Heatwave: Breaking Records and Sweltering in Day and Night


On Tuesday, Phoenix’s 19th consecutive day of sweltering temperatures of 110 degrees Fahrenheit or higher was expected to break the record for major US cities.

The nighttime has provided little respite from the extreme heat. Monday’s overnight low of 95 degrees Fahrenheit in Phoenix broke the previous record of 93 degrees, set in 2009. It was the eighth consecutive day of temperatures exceeding 90 degrees Fahrenheit, another record.

It is “pretty miserable” when there is no recovery overnight, according to meteorologist Matt Salerno of the National Weather Service.

Phoenix’s Prolonged Heat Wave Stands Out 

The length of Phoenix’s heat wave is notable, even during a summer in which much of the southern United States and the rest of the globe have been baking in record temperatures, which scientists say are fueled by climate change.

According to experts, the situation in the metropolitan area known as the Valley of the Sun is far worse than a brief temperature rise and poses a threat to the health of many.

Katharine Jacobs, director of the Center for Climate Adaptation Science and Solutions at the University of Arizona, stated, “Long-term exposure to heat is more difficult to endure than single hot days, particularly if it does not cool off enough at night to sleep well.”

According to David Hondula, chief health officer for the City of Phoenix, this will likely be one of the most notable periods in terms of fatalities and illnesses. Our objective is for that to not be the case.

Phoenix’s Sweltering Streak: Breaking Records with 18 Consecutive Days Above 110°F (43.3°C) as Heatwave Continues

The last time Phoenix did not achieve 110 F (43.3 C) was on June 29, when the temperature only reached 108 F (42.2 C). The record of 18 days above 110 degrees, which was tied on Monday, was first set in 1974, and it appeared that it would be broken by the end of the week as temperatures were predicted to exceed that mark.

According to Randy Cerveny of Arizona State University, who coordinates weather record verification for the World Meteorological Organization, the Phoenix heat wave has both long- and short-term causes.

“Over the past few weeks, a very strong upper level ridge of high pressure has persisted over the western United States,” he explained.

This high pressure, also known as a heat dome, has been cooking the Southwest for weeks, and when it shifted, it moved closer to Phoenix than ever before, according to Smith.

The entire southern United States has been under a heat dome, with temperature records being broken from California to Florida, and the globe has been the warmest on record for the majority of summer.

Smith stated that the high pressure in the southwest prevents rain and clouds from providing relief. Typically, the monsoon season in the Southwest begins in mid-June with rain and clouds. But since mid-March, Phoenix has not received any measurable rainfall.

“Although it is always hot in Phoenix during the summer, this heat wave is extreme and unrelenting,” said Jacobs. Given that the most reliable projected impacts of climate change are those that are directly related to the rise in global temperatures, this is unfortunately a portent of things to come.

NOAA reports that since 1983, the average daily summer temperature in Phoenix has risen 3.6 degrees (2 degrees Celsius), the daily high has risen 3.2 degrees (1.8 degrees Celsius), and the nighttime minimum has risen 4.4 degrees (2.4 degrees Celsius).

“Climate change and urban heating are certainly exacerbating and increasing the frequency of warmer temperatures,” Smith said.

And this is hazardous for numerous populations.

“Heat waves are especially lethal for the homeless, those who work outdoors, and those with inadequate air conditioning,” said Jacobs. Staying hydrated is particularly difficult for the elderly and those with underlying health conditions.

Such humidity can wreak havoc on Indian Country. According to Jacobs, approximately 30 percent of the Hopi and Navajo populations lack flowing water and air conditioning and do not live near cooling centers. This is especially unjust because “tribal members have contributed very little to greenhouse gas concentrations,” as stated by the author.

Another aspect of heat waves that disproportionately affects certain communities is the urban heat island effect, where cities are warming because of buildings and lack of trees and greenspace, said Dr. Jonathan Patz, a professor of health and the environment at the University of Wisconsin-Madison.

A study published in the journal Nature Communications two years ago found that people of color experience more extreme temperatures than non-Hispanic white people, and that the impoverished experience hotter temperatures than the wealthy.

The majority Hispanic neighborhoods of Phoenix typically have a smaller tree canopy than the rest of the city.

And one of the hottest neighborhoods in the city is Edison-Eastlake, a historically Black neighborhood east of downtown that has become majority Latino, where in past years temperatures have reached as much as 10 degrees higher than other parts of the city.

Arizona State University researchers are conducting a heat study of the neighborhood, which is home to the largest collection of public housing in Arizona, to gauge whether temperatures ease as it undergoes redevelopment aimed at better protecting residents from extreme heat. Any conclusions so far have not been made public.

Hondula, the Phoenix heat officer, was involved in that study several years ago as a researcher at the university.

“It’s very clear that heat has disproportionate impacts on some communities,” he said. “That’s where we can and should work.”

Read also: Nature’s Respite: Improved Weather Eases La Palma Wildfire in Spain’s Canary Islands

Source:  New York Post,

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