A prolonged and substantial heat wave has settled over much of the United States -- along with numerous other locations in the northern hemisphere around the globe -- and that heat wave has been particularly severe in the Phoenix, Arizona area.

In fact, according to Maricopa County public health officials, there have been at least 18 heat-related deaths in the county thus far this year, with another 69 deaths this year currently under investigation to determine if they were also related to the extremely high temperatures, NBC News reported.

As terrible as that news is, and despite the fact that the area has endured record-breaking heat in recent weeks, the number of heat-related deaths this year is on pace to be lower than the total number of heat-related deaths that occurred in Maricopa County in 2022.

Deadly heat wave in Arizona's Maricopa County

On Wednesday, the Maricopa County Public Health Department issued its weekly report which revealed that, as of July 15, there have been 18 confirmed "heat-associated deaths" so far, with the first such death occurring on April 11, with another 69 deaths that are currently "under investigation" as being suspected of being associated with the heat.

Compared to the same point in 2022, however, there had been 29 confirmed heat-associated deaths with another 193 deaths under investigation, with the first confirmed heat-related fatality occurring on March 13 of that year.

The report further indicated that more than 60 percent of the deaths claimed the lives of individuals over the age of 65, nearly 80 percent involved outdoor activity -- only four deaths occurred indoors -- and around one-third of the heat-related fatalities involved homeless individuals.

Of those four indoor deaths, it is notable that three of the victims had "non-functioning" air conditioning units while the fourth victim's unit was "not in use." The report also noted an uptick in heat-related hospital visits, about two-thirds of which involved men -- and with the victims of heat-related illnesses being spread out across the age ranges -- but only about 8 percent of the visits involved homeless individuals.

NBC News reported that Maricopa County Public Health Department medical epidemiologist Dr. Nick Staab said, "We truly believe all these heat-related deaths are preventable," and added, "We’re seeing increasing numbers, and so obviously that’s why we want to draw attention to this to make sure everyone has a plan."

The currently reported numbers of heat-related deaths will likely be revised upward going forward, the doctor noted, as it can take "weeks or months" to determine if certain deaths are related to the heat. It was also noted that there were a total of 425 heat-related deaths in Maricopa County last year, more than half of which involved homeless individuals and about two-thirds of which involved the use of drugs or alcohol.

Heat wave likely caused by cyclical El Nino weather pattern

Forbes reported earlier this week that the Phoenix area broke a heat-related record first set in 1974 on Tuesday when it experienced its 19th consecutive day with a recorded high temperature over 110 degrees Fahrenheit, and that trend was expected to continue until at least early next week. Likewise, the city also set a new record with nine consecutive nights in which the low temperature remained above 90 degrees.

But, as noted at the outset, it is not just the Phoenix area that is broiling under an oppressive heat wave, as the HEAT.gov site currently notes that an estimated 118 million Americans are under some sort of heat-related alert, be it an advisory, watch, or warning, with the vast majority of those alerts being in the Mountain West, the Southwest from California to parts of New Mexico, and across the Southeast from central Texas to Florida and Georgia.

To be sure, there are those who have sought to blame the hot temperatures on man-made climate change, but in reality, it is actually mostly caused by a "natural climate phenomenon" known as El Nino that is cyclical and occurs every two to seven years, on average, according to the National Weather Service.

The El Nino weather pattern is caused by warmer-than-average surface waters in an equatorial strip of the Pacific Ocean that typically results in above-average rainfall and temperatures for much of the United States during the Summer months, when the pattern is weakest, and then causes wetter-than-average and warmer-than-average weather for the southern half of the nation during the Fall and Winter months when the pattern is strongest.

Regardless of the cause of the heat wave, the only thing that people can actually do to combat it is try to limit outdoor activity and stay inside an air-conditioned environment as much as possible, stay hydrated, and seek medical attention if experiencing the symptoms of a heat-related illness.