The Heat
Cholla Express: August 2020
Except for those living up in the pines, it’s blazing hot in Arizona right now.
This won’t be breaking news to anyone reading this newsletter. It’s blazing hot in Arizona every summer.
But the heat feels more oppressive this year.
Maybe because it has actually been hotter, or maybe it’s a combination of the usual summer heat along with the general despair at, well … everything else going on.
I don’t know if people ever acclimate to this kind of heat. The kind of heat that gives you a scalding burn when you accidentally touch the medal on your seat belt. The kind of heat that hits you like a wall as soon as you open your front door — even at 7:00 am.
I’ve lived in a different desert, and it wasn’t this hot. In Palm Desert (just east of Palm Springs in the Coachella Valley of California) the summer is hot, but it cools off more at night. Probably because it’s less dense, with less asphalt to absorb the heat. One of the weather headlines this past month in Phoenix was that the “lows” were frequently above 90 degrees.
The only other place I’ve lived is the Bay Area of California. In San Francisco it’s basically the same weather all year round. Always moderate, regardless of the season. A day in January might be warm and sunny; a day in August might be cold and damp.
I will say this about summers in the Valley of the Sun: At least you can go outside if you really want to, unlike the icy winters in the Midwest and Northeast. I wouldn’t trade those winters for these summers, even with an average temperature of 99 degrees.
And there are things you can do to stay cool: Swimming pools, sprinklers, water parks, lakes, the Salt River.
Alas, many of these aquatic activities have been hampered by Covid-19. Unless you have a pool of your own, you were mostly out of luck in July. Water parks and Salt River Tubing have been closed all month (and counting) due to an executive order by the Governor. Some city-run public pools are back open with limited occupancy and social distancing requirements, but others remain closed. Saguaro Lake and Lake Havasu are open, but I’ve heard they’re so crowded that, if you care about social distancing, don’t bother going.
Monsoon season can bring much needed relief from the scorching heat. During my time in California, the summer storms were what I missed most about Arizona. Palm Desert has a lot of wind, but even less rain than Phoenix. The Bay Area gets rain, but there’s nothing quite like a warm lightning-and-rain storm in the Valley, and the wet desert smell that comes with it.
If it doesn’t quite rain, though, all you get is increased humidity and dashed hopes.
Typical of the year 2020 AD, that’s mostly what we got in the month of July. One night in the East Valley we did get a storm, with rain and lighting and refreshing smells and all. It was a temporary reprieve, but a welcome one.
Here’s hoping for some major downpours in the month of August.
Staying Cool: A Modern History
The modern history of staying cool in Phoenix is one of shade, swimming, and air conditioning.
By modern history, I mean since the Swilling Irrigating Canal Company started digging new canals and planting crops in the late 1860s.
In ancient times, the land was inhabited by the Hohokom Native Americans. They were the first to dig canals in this Valley, and they lived here successfully for hundreds and hundreds of years before they mysteriously vanished in the mid 1400s. The best guess for their disappearance is that a severe drought caused food shortages, and they went looking for new lands.
For modern settlers, large trees were the first line of defense against the heat. They grew in abundance in the fertile soil of the Salt River Valley. This is from a newspaper clipping from the year 1915:
Wherever one goes in the Valley there are trees—along city streets, lining the country roads, guarding the canals, patrolling ranch and orchard, are the lovely shade trees—ash, olive, cottonwood, eucalyptus, pepper and palms
But many of the trees — especially the Cottonwood — absorbed so much water along the canals that, as the city grew and developed, much of this beautiful vegetation was chopped down. This trend has sadly continued into the present, as it seems like each new golf course renovation or construction project leads to the felling of mature trees.
In early Phoenix, the wider sections of canals were used as swimming holes. Before the age of ubiquitous air conditioning, these shaded swimming holes would have been essential for locals trying to stay cool in the summer.
Some folks even got creative:
In the 1930s and beyond, teenagers often congregated on its banks and the truly brave would “freeboard” the canal, carefully balancing on a homemade board while being pulled along by an old Model T.
Eventually, people started filling up holes with well water, or siphoning water away from the canals to create little homemade pools away from the dug canals. It was only a matter of time before concrete pools in backyards and public areas replaced natural swimming holes as the go-to cooling mechanism for Phoenicians.
The real game-changer for staying cool, however, was the industrialized manufacture of air conditioning systems. Not only did air conditioning provide relief for Valley natives, but it also led to a population boom in the 1950s. Air-cooling systems were invented in the early 1900s, but it wasn’t until the post-WW2 era that our industrial capacity allowed them to become widespread. By 1951, over ninety percent of Phoenix residents had AC. It’s no coincidence that the next decade would see a four-fold increase in population.
Without air conditioning, people might still be sleeping outside underneath a canopy of wet sheets, and Phoenix certainly wouldn’t have become the fifth-most populous city in America.
Legendary home builder Del Webb summed it up best: “The air conditioning apparatus has enabled Phoenix to meet and conquer the summer heat, long the bane of southwestern existence.”
Sources (besides those already linked):
Luckingham, Bradford. "Urban Development in Arizona: The Rise of Phoenix." The Journal of Arizona History 22, no. 2 (1981)
“A Brief History of Phoenix” by Jon Talton
Photograph by Walter J. Lubken, U.S. Bureau of Reclamation via SRP
Summer Storms
This summer saw a streak of over 100 days without measurable rainfall in Phoenix. That’s harsh.
The longest streak ever without measurable rainfall was 160 days, ending in June of 1972.
There are two types of summer storms in Arizona. The monsoon and the haboob. This segment will cover the scientific causes of these two types of storms, and then I will offer an unscientific theory about their frequency.
To explain the science of monsoon storms, I’ll leave it to the late great Clay Thompson, who wrote a daily Q & A column called “Valley 101” for the Arizona Republic for nearly twenty years.
Here’s a segment from a column published on July 4, 1999:
Monsoon comes from an Arabic word, mawsim, which means “season.” It is usually taken to mean weather brought on by a seasonal change in the winds, and that’s just what happens in Arizona
Every year, generally in late June or early July, atmospheric conditions combine to push the jet stream to the north. This allows winds to flow into the state from the south or southeast. These winds carry a lot of moisture from the Gulf of California and the Gulf of Mexico
The humid air means:
Your evaporative cooler isn’t going to be as effective as it was when the air was dry.
There probably will be a lot of storms, some of them loud and nasty.
You should go to San Diego and stay there until sometime in mid-September.
There probably will be a lot of storms because when that moist, cool air from the south hits hot air radiating up off the desert floor, it creates a witch’s cauldron of towering clouds that usually reaches the boiling point in the late afternoon or early evening.
These storms can be powerful, and they can be dangerous. The winds can be fearsome and the lighting spectacular. (Be careful: A couple of years ago, up in the mountains, a man was relieving himself on a pine tree when the tree was struck by lightning. He survived, but can you imagine?)
When does monsoon season start?
That designation has changed over time. It used to start when we saw three consecutive days with a dew point average above 55 degrees. But now, instead of starting at a designated level of air moisture, monsoon season starts on a specific date, June 15th.
A haboob is a dust storm. The name first appeared in 1971, but didn’t catch on until the early ‘00s. Like the monsoon, the name is taken from Arabic, because similar dust storms frequently happen in Sudan.
According to a recent article by ABC-15 meteorologist Amber Sullins:
Haboobs are giant walls of dust created from high winds rushing out of a collapsing thunderstorm.
Cold air in front of the storm rushes down at an incredible rate, picking up massive amounts of dust and sand and blowing them into the air.
As the dust storm builds, it can completely block out the sun, making it nearly impossible to see just a few feet in front of you.
The wall of dust typically reaches heights between 1,500 and 3,000 feet and can stretch as far as 100 miles wide. To put that into perspective, that's the distance between Phoenix and Tucson.
(Both of the links above feature cool videos of monster dust storms. Highly recommended.)
Here’s my unscientific theory about summer storms. I think the ratio of haboobs to monsoons has changed over the past few decades. Growing up in the ‘90s and ‘00s, I remember frequent monsoon storms. Not so many memories of dust storms. In the past five years, it seems like haboobs are more common than thunder-and-lightning storms.
Are we now seeing a higher ratio of dust storms? Has anyone recorded their frequency over time?
I could do a thorough investigation into this matter, but I’ll leave it for next summer, when perhaps there will be more storms to talk about.
Photograph: McLaughlin, Herbert, “Storm over Monument Valley.” Arizona State University Library: Greater Arizona Collection
Final Thoughts
No “links and news” section this month, because I didn’t feel like thinking about the news, and there are various weather-related links in the previous segments for readers to explore. It may return next month.
I will instead leave you with a photo taken a few weeks ago in downtown Phoenix. Slightly overcast.
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Thanks for reading!