The weather this week has been brutal. The last hike I did in the upper 80s left me heat-stressed despite drinking lots of water. I stop exerting any effort at all in the 90s. In the 100s all I begin to estivate.
However, there were power outages all over the place. It is easier to do them than to maintain the electrical lines in a safe and usable condition for hot weather. I’m really hoping the price of batteries drops to where I can reasonably afford to install them. Won’t have to worry about the outages then.
Every summer a big high pressure system sets up over the Great Basin Desert. That’s Nevada and Utah. The air heats up. Hot air expands producing high pressure. The Basin is at about 4-5,000 feet of elevation. Air flows out in a clockwise fashion into the surrounding areas. The surrounding areas in the south are the Mojave Desert which is mostly at 2-3,000 ft. The incoming air gets compressed heating it. Death Valley at 250+ ft. below sea level is the lowest point in the Mojave and because of that experiences the most compression. Ostensibly the hottest location in the world.
The Mojave is already insanely hot. Then this even hotter air comes blasting in. It doesn’t stop at the mountains north of LA. The hot air climbs and is cooled, squeezing any possible hint of moisture out. It then pours out of those mountains down into the low elevation valleys that are the Greater Los Angeles Area, picking up great speed, recompressing, and heating even more. (Known in meteorology as katabatic winds.) Relative humidity plunges into the teens and single digits. These are the famed Santa Anna winds.
The low humidity fails to hold in any heat at night, often resulting on 40 degree temperature swings.
Not the Satan winds, tho they seem hot as hell.. Not the Santa Anita winds, tho Santa Anita does feel them. Not the Santana winds, though I’m sure Carlos is extremely familiar with them. I hear newscasters brutally mangle the name of these winds all the time. These fires turn tiny sparks into raging infernos. They suck the water out of your lawns and gardens, contributing to the already extreme drought.
But… we still love LA. 🙂
Triple-digit weather combined with direct sun and physical effort can kill you very quickly. You can’t sweat fast enough to cool off and you can’t carry enough liquids to keep up with the sweating.
The best way to dress in the sun for super hot and dry weather is layers of loose cloth. It provides shade to the skin yet allows air to circulate and traps some moisture next to our body. The the body works very hard to keep the skin surface close to 100% humidity thru insensible perspiration at all times. It is a very large source of water loss.
Skin in direct sun can climb to 104F (40C) if you are healthy and more if you are dehydrated. A person’s standing body is hit by 500 watts of solar heat energy continually, depending on body size. A sun bather perpendicular to the sun can receive double that. This is in addition to the heat from the air.
In super hot and moist weather you still want shade but you don’t want clothing because water doesn’t evaporate well in high humidity, You want to give the water every chance possible to evaporate. We lost our fur because it was advantageous to our hunting style – “persistence hunting.” Furry people overheated when chasing down game.
In the military, they taught us to always check our urine in hot weather. Needs to be clear to light. Medium to dark yellow is a sign you need to drink more. If you suffered from any dehydration related illness, you written up and punished for to obey standing orders.
Someone who is acclimated will last a lot longer. Unless you’ve been an outdoor laborer for a while, I guarantee you are not acclimated. Most of the urban population does not ever acclimate, even if they are in good cardiovascular condition. (I know I don’t.) Too much air conditioning in our lives. Most of us have to make an effort to drink enough in hot weather because the thirst reflex doesn’t kick in properly. People simply forget to drink and next thing they know, they get head aches and feel faint. Welcome to hyperthermia. So be safe!
If you are vulnerable to heat issues – the very old, the very young, the ill, – and the AC goes down, be extra sure to drink more water than you want. Stay inside and close the curtain on the sides of your exposed to the sun. On the other side, open the window and hang wet towels in front of it. Take cold baths. Give cool baths if you are a caregiver. Get wet and let nature cool you off. Keeping your head cool is the most important thing of all. An overheated brain is what kills you.
Please don’t be this person!
June 20, 2021 at 09:14
Oh, goodness. That is way too hot. It gets about 90 degrees up here and I’m just done.
June 19, 2021 at 18:53
“Like” is not really what I want to express here… Las Vegas is just as hot and getting hotter every year. We are already setting record highs of 114 and above and we know it will get hotter. As I recall, last summer saw 120 a few times. Sitting in this urban area with cement over everything, it never cools down at all. Last year, again, we had times of triple digit temperatures – all night long. It’s been the hardest thing for the outdoorsy me to learn that I can’t even pretend to bear this. I hole up from June to September in my little tin can with two fans, a cold water humidifier, and one a/c running like hell to keep my 25 foot RV at a mere 100 degrees inside. I finally give up and cover every window with foil lined with cardboard. I’m naked, and keep a silky like robe by the door in case someone knocks or I have to run outside for some reason. We freeze bottles of drinking water in the big freezer (the small one on the refrigerator ceases to freeze anything) and use them to roll around on our seats to cool them off, hold in our laps, etc. and as they defrost we have cold water to drink. Hike? I barely manage to walk to the bus stop or the nearest store for more water. The worst part for us is my hubby dehydrates (quite unusual for a kidney patient – but he is a bit unique because of the cause of his kidney failure), and it becomes difficult to dialysize him because, of course, the treatment dehydrates him even more. It is so brutal I wonder sometimes if we are going to survive.
But the worst part to me is from the time the temperature reaches about 60, every bus, store, business of any kind cranks up the A/C and starts keeping interior temperatures sometimes literally as low as 50 degrees. I really believe that walking in from 110 to 60 and then back out to your car which has been baking in the sun, or half a mile to the nearest bus stop (LV is determined no bus stop be nearer than half a mile to anything), waiting half an hour in the heat, then getting on a bus that’s about 60 degrees… sure it’s a relief, but I really think it is too much of a shock for your body. I actually carry a JACKET for going INDOORS. *eyeroll*
Thanks for your, as always, insightful and intelligent analysis and excellent advice on surviving the heat – and being sensible about when and where to hike and what to wear (or not) if you do. I really hope this reaches everyone who needs to hear it. I loved the heat in New Mexico, but it cooled at night, and in monsoon season it actually rained like mad every afternoon and cooled it down considerably (at least where I was). I hiked and kayaked and spent all summer outdoors. Sigh. I miss it. It is SO WEIRD to me to hole up in summer, and be able to go outside in winter (all my life I’ve hated winter because it drove me inside!)
One little thing I want to add, because I see people doing this all the time and it makes me just cringe. Please remember that your pets feel the heat, too. Let the dogs out to play at night or in early morning or evening. If you live in an apartment and walk the dog – if you wouldn’t walk barefooted on that pavement, your DOGS FEET BURN too. You can get little booties. Yep, looks silly and the dog may not like them – but it’s better than letting their feet burn. And a smart dog – well, my Sheltie would meet me at the cabinet with his leash, and his paw held out for his boots. Keep in mind they’re wearing a fur coat and can’t take it off. If you have a double coated dog like a husky please, please consider taking them to the groomer and having that big coat cut off in the summer if you are in a super hot climate. Make sure all your pets, whatever they are, have plenty of cool, fresh water. If they are outdoors, make sure they have shade with air circulation available all day long. Laugh if you want, but if your pet is black (like a black lab) consider getting them some kind of clothing that is white or light colored and loose.
Okay. Enough. Enjoy and be safe and thanks Fred!
June 18, 2021 at 02:58
I posted the following comment on Kensunwalker’s blog post after reading your comment there about Tuesday’s hike in northern Arizona to Stoneman Lake and temps being in the 90s. It seems appropriate to repost it here as well.
I don’t think the 90s would have bothered me that much, though without shade the sun makes it feel a lot hotter. Back in August 2005 I was at Burning Man in far northern Nevada on a dry lakebed playa in the high desert (~4,000 feet) for the third time. It got into the low to mid 90s for a couple hours during the day, but quickly cooled off to probably the mid 40s at night. Probably single digit humidity and always a breeze. The sweat never had a chance to make you wet — it just left a white powder on your skin at the end of the day! There were plenty of Californians in attendance and some were complaining about the heat and threatening to pass out.
Coming up from Phoenix, the 90s felt like a relief after being in humid 110 degrees. It’s a clothing-optional event and there was plenty of skin and nudism on display. But as desert rats, we kept some covering on to guard against sunburn, being short on sunscreen. Crazy costuming is de rigueur there and we mostly wore red long underwear and walked around together as the Red Daves.
But one midnight even though it was somewhere below 50 I ventured out of our tent au naturel to use the porta-john and then just kept wandering through the massive camp for a few minutes, passing some of the night owls strolling through the massive temporary campus. Probably a third of the 30,000 attendees stay out all night. The place is like Vegas — it never really sleeps. Night is the time the wind stops so there was no wind chill to blow through me. The only looks or comments I got were people asking if I was cold. I was, a bit, but the feeling was exhilarating nonetheless.
Nudity is completely acceptable at Burning Man though only maybe 10 to 20 percent of attendees wander partially or mostly nude and nobody cares. That may be a conservative estimate. Or maybe it just seems like half the people there are naked, because it is so out of most folks’ normal routine. Interestingly I seem to remember more females than males displaying some degree of nudity. There is even an annual bike parade of topless women celebrating breast health and breast cancer awareness. Many hundreds of women pedal a parade route ending at a big party.
One of the most unusual events for me at the time was at an earlier Burning Man (2003) when I participated in a group nude photo shoot of about 125 people, by a photographer well-know for this sort of thing, but who was not Spencer Tunick. We were all spread out single file in a chevron shape, and photographed facing different directions. It was great fun, but the weirdest part was assembling the group, which met just inside the event’s perimeter fence to disrobe. When I was done, as I looked up, about 40 people had crossed the fence walking away from me across a perfectly flat, featureless, other-worldly lakebed toward the gathering point, with a mountain range in the far distance. The only thing I could think of in that unique moment, as the mostly thin figures ambled, some slightly wobbling away was that I was on a strange planet and these were aliens, not unlike something out of “Close Encounters of the Third Kind” just peacefully going to meet their leader.
June 18, 2021 at 10:32
Never been to Burning Man. I understand it has gotten very expensive.
June 17, 2021 at 19:35
That big high pressure dome has been hovering over Arizona lately and it’s starting to feel like we’re gonna get Santa Ana winds over here. Our monsoon season officially started Tuesday and on schedule, we got a dust storm and high winds. I even lost a branch off my four-year old desert willow tree in my front yard.
As a third-generation Arizonan, I am used to the heat and have spent much of my life out in it. I am definitely acclimated. But I know the dangers and have had a few experiences with both heat exhaustion and dehydration. Nothing terribly serious. Once when I was 20 and doing pick and shovel work repairing the dirt driveway up the hill to my dad’s house, I think it was heat exhaustion. Another time a couple years ago, when I was 67, hiking in the hills near my home, I ran out of water toward the end of my hike. I was starting to get muscle cramps that I couldn’t relieve by stretching and walking. I think I was getting dehydrated. Now I usually take some Gatorade with me to keep the electrolytes up.
So, I stay safe, even though I sometimes go out hiking (or working in my backyard) in the middle of the day in the middle of the summer, in Phoenix, when it is well over 100, usually more like 105 or 110. It has been 115 and 117 here this week., although I haven’t been out in it for extended periods. I am finally having to admit that my age is catching up to me a bit and am being more careful and avoiding the very hottest days and times of the day when out hiking. I still sometimes do it in the nude, though, at least when I can be sure I am alone!