Yet another reason not to do C2C/Skyline in the summer.

[cynthia23]

James Cornett (our excellent local naturalist) had an article in today's Desert Sun (maybe somebody could supply the link? ) in which he went around on an average summer day in the Coachella Valley (temp 112) using an infrared gun to measure the temperature of various objects. South-facing rock surfaces were an average of 146 F. (!!) This gets to the topic of 'why it's such a bad idea to hike Skyline during the warm months." Even if you start in the middle of the night, the mountain itself is holding a tremendous volume of stored heat. The ambient air temperature doesn't necessarily reflect the temps you will actually be experiencing at ground level. As soon as the sun rises, you start getting a 'griddle' effect of waves of heat radiating off every rock you pass or step on. It's kind of like being a human pancake. Except without the maple syrup.

[bluerail]

.....

[Wildhorse]

We have all felt the heat coming from the rocks, but I never imagined that the temperature would be as high as 146. It does make one pause to know how very hot the rocks are.

Even here in cool San Diego, on Cowles Mountain the rocks become quite warm and when the sun rises on a breezeless morning, a hiker becomes hot very fast even while the air temperature is only 70 degrees. Rescues are needed frequently. I think I even read of a death or two there every year.

What a vivid image: human pancake. It explains so well what happens to us.

And yet, the human spirit resists restraint. It resists letting any day pass without spending time on a mountain here in southern California.

[hvydrt]

mmmmmmm, pancakes

[cynthia23]

The Simpsons explain so much in life.

[SoCalJim]

Wildhorse, just to be clear, there isn't "a death or two" on Cowles every year. More like one every several years. Last was August 2009 when a 67 year old who was a regular on Cowles died of a heart attack. Now, if stupidity was more deadly, we'd have an epidemic of deaths on Cowles, not that it's unique in that respect...

[Wildhorse]

Yesterday the temperature on Cowles reached only 87 degrees. That was the temperature on the day the man died there in 2009 to which SoCalJim has referred.

At Cowles yesterday, I sat on a south facing rock around sunset. It was warmer than my skin, but not burning hot. I would guess that it was about 105 degrees.

I read here, http://www.nist.gov/fire/fire_behavior.cfm, that skin begins to feel pain at 111 degrees and will incur a first degree burn at 118 degrees. At 131, the burn is second degree. At 140 it turns numb. At 162 it is destroyed on contact. At 146, the temperature James Cornett recorded, it would not last long, but it would not hurt:)

[zippetydude]

Hmmm, interesting numbers. I can tell you I enjoyed relaxing in the shade in 122 degree weather at the end of June this summer with nothing cooling my skin but a breeze. I'm not sure to what degree perspiration cools the skin, but apparently it's enough to keep it from damage as long as you have plenty of water and can stay in the shade.

z

[Wildhorse]

Zippetydude, I think that is it. The breeze and the shade, plus sweat, are a natural swamp cooler. I think that the temperatures in that report are skin temperatures and our sweat and a breeze keep skin temperature down when the air is hot, as long as the sun is not hitting it directly, or we are not touching something that is very hot, such as James' rock.

I think it is impossible to say at exactly what temperature and sun exposure our bodies fail to keep cool. And some of us do much better, or worse, in high heat than others. I have a friend who can climb the skyline in heat that would surely kill me.

[towbradley]

Laying on hot asphalt hooking and booking cars for stranded aaa members(15 or 215 freeways,take your pik) will give one literally asphalt burns right through your cloths if you stay too long in the pron position........you gotta love the pain.