"California Highway Patrol, Indio office."
"I have a question regarding highway 86S."
"I can help you," says the receptionist.
"Is it permissible to walk along the new section of the highway south of 66th Avenue?"
"No. It's a four lane highway and you are not allowed to walk there."
I am not convinced that her answer is correct; I resort to one of my little white lies.
"Thanks for the info. May I please have your name and title? I am writing an article for a newspaper and I need to cite my sources."
She says just a minute and puts me on hold. Then a CHP officer picks up the phone and tells me that it is O.K. to walk along the old 86 as well as the new 86S. But his curiosity is aroused.
"Why do you want to walk in this summer heat?"
"Well, some of us like the challenge of walking in an extreme environment."
"Then, why don't you walk in Death Valley?"
"I already have. However, though the Salton Sea temperatures are about 10°F lower, the much higher humidity there results in a higher heat index."
"Good luck. But be careful."
I had walked the 180-mile length of Death Valley in 1998 and the 156 miles from Badwater to the top of Mt. Whitney in 2003. Death Valley is certainly hot, but it is also very dry. The humidity in summer is usually less than 10%. Just as there is wind chill factor to measure the effect of wind on cold temperatures, there is the corresponding heat index. It shows the apparent temperature for various combinations of temperature and humidity.
The heat index is the "feels like", or apparent, temperature. As relative humidity increases, the air seems warmer than it actually is because the body is less able to cool itself via evaporation of perspiration.
| Relative Humidity (%) |
Air Temperature (°F) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 70° | 75° | 80° | 85° | 90° | 95° | 100° | 105° | 110° | 115° | 120° | |
| 5% | 64 | 69 | 74 | 79 | 84 | 88 | 93 | 97 | 102 | 107 | 111 |
| 10% | 65 | 70 | 75 | 80 | 85 | 90 | 95 | 100 | 105 | 111 | 116 |
| 15% | 65 | 71 | 76 | 81 | 86 | 91 | 97 | 102 | 108 | 115 | 123 |
| 20% | 66 | 72 | 77 | 82 | 87 | 93 | 99 | 105 | 112 | 120 | 130 |
| 25% | 66 | 72 | 77 | 83 | 88 | 94 | 101 | 109 | 117 | 127 | 139 |
| 30% | 67 | 73 | 78 | 84 | 90 | 96 | 104 | 113 | 123 | 135 | 148 |
| 35% | 67 | 73 | 79 | 85 | 91 | 98 | 107 | 118 | 130 | 143 | |
| 40% | 68 | 74 | 79 | 86 | 93 | 101 | 110 | 123 | 137 | 151 | |
| 45% | 68 | 74 | 80 | 87 | 95 | 104 | 115 | 129 | 143 | ||
| 50% | 69 | 75 | 81 | 88 | 96 | 107 | 120 | 135 | 150 | ||
| 55% | 69 | 75 | 81 | 89 | 98 | 110 | 126 | 142 | |||
| 60% | 70 | 76 | 82 | 90 | 100 | 114 | 132 | 149 | |||
| 65% | 70 | 76 | 83 | 91 | 102 | 119 | 138 | ||||
| 70% | 70 | 77 | 84 | 93 | 106 | 124 | 144 | ||||
| 75% | 70 | 77 | 85 | 95 | 109 | 130 | 150 | ||||
| 80% | 71 | 78 | 86 | 97 | 113 | 136 | |||||
| 85% | 71 | 78 | 87 | 99 | 117 | 140 | |||||
| 90% | 71 | 79 | 88 | 102 | 122 | 150 | |||||
| 95% | 71 | 79 | 89 | 105 | 126 | ||||||
As the heat index rises, so do health risks. When the heat index is 90 to 105, heat exhaustion is possible. When it is above 105, it is probable. Heatstroke is possible when the heat index is above 105, and very likely when it is 130 and above.
Physical activity and prolonged exposure to the heat increase the risks.
Salton Sea weather records indicate summer highs between 105°F and 115°F, with a humidity range of 40% to 80%. Thankfully, the humidity is usually lowest when the temperature is highest. Still, the heat index for 110°F with 40% humidity is 137, whereas the same for Death Valley's 120°F with 10% humidity is 116.
The human body cannot dissipate built-up body heat by radiation or convection once the ambient temperature rises above approximately 98°F. The only way for the body to stay cool is by evaporation of sweat. And high humidity makes it harder for the sweat to evaporate, resulting in excessive buildup of body heat.
I had kayaked the Sea in autumn a couple of years after my first Death Valley walk. That's when I learned about the high humidity in the area. I particularly remember being told about the large number of rescues of fishing boats in the summer. That had piqued my interest and I was eager to brave someday the deadly combination of high heat and significant humidity. Another factor drawing me to the area was the fact that a walk around the Sea would be entirely below sea level. All right, you nitpickers, for a short stretch, the elevation does rise to 15 feet above sea level. Temperatures decrease three to five degrees Fahrenheit for every thousand feet of elevation gain, but the Salton Sea was going to provide no such relief.
The Salton Sea did not exist 100 years ago. It was formed in 1905 as a result of human folly. In 1901, canals were dug to divert water from the Colorado River to the fields of the Imperial Valley. However, the silt from the river soon clogged the canals. A "temporary cut" in the river was breached by unseasonal floods, and for a year and a half the entire Colorado River changed course and emptied into the Salton Trough, a below-sea-level basin. There were no dams on the Colorado at that time, and the lake rose almost four feet a week during the peak flow period. When the flow was finally contained, a 450-square-mile lake was created in the middle of the desert. The surface elevation of the new lake was, and still is, 228 feet below sea level. The lake is about 40 feet deep at its deepest point.
During the first 20 years, the lake kept shrinking; the inflow of water from the farm runoff was less than the water loss from the evaporation. Since then, the increased runoff has stabilized the Sea at its current 350-square-mile size. The salinity of the water is, however, another story. The Colorado River water is salty and the Sea has no outlet. The water lost through evaporation leaves the salt behind. Currently, the Sea is about 25% saltier than the ocean. Unless something is done to reverse the trend, the salinity is expected to keep increasing.
Thousands of pelicans call Salton Sea home during autumn and winter.
My plan was to encircle the Sea by walking on roads rather than along the shoreline. There was just too much mud, too many barnacles and dead fish, and the usual man-made structures that blocked the path. I estimated the total distance at around 120 miles and debated whether I should allow six or seven days. In the end, I opted for six 20-mile days. Still, as a veteran of two Death Valley walks, I felt that this walk wouldn't be much of a problem.
Most athletes who walk, run or bike in the desert heat depend upon a support vehicle for food, water and emergency help. I had such a support on my second Death Valley trip and a modified form of it on my first. I personally feel that an outing is not really exciting unless there is some uncertainty and stress due to possibility of failure.
... Each of us, in our daily lives, tends to adjust to this invisible stress point. If a man lives just up to it, he can lead a happy and productive life. If, on occasion, he lives just a little over it, he finds that often these are the periods in which he learns "by running scared". If, on the other hand, a man lives too far over his stress point, that man will tend to panic. Sooner or later such a practice results in disaster.
But the real problem, for most of us, lies in setting our sights too low. Mainly because of fear, perhaps 95% of us live too far under our stress points. For those who dare too little, the penalty which must be paid, while perhaps not as sudden as for those who dare too much, is equally sure and certain. Life becomes dull and meaningless. Those who dare not become so much beef on the hoof; they exist, but they do not live ...
I decided that I would walk unsupported during each day, carrying all my water, food, emergency items etc. That's usually not a big deal but, in the heat, I would have to carry at least three gallons of water, making my total load around 35 pounds. Carrying that much weight, in turn, would require a lot more expenditure of energy and even more consumption of water. Any big pack I carried would also greatly hinder sweat evaporation. There was only one way out of this dilemma. I had to find something to wheel the load rather than to carry it.
After trying out a few devices, I settled on a baby jogger with 24-inch rear wheels. The jogger itself weighed 33 pounds. Nonetheless, I was able to push a load of 40 pounds uphill without undue effort.
Initially, I positioned a cooler near the front, an easy placement, but it made turning the jogger quite difficult. A friend of mine solved the problem by moving the cooler towards the rear by resting it on a sturdy basket. The basket was to be used for carrying other supplies. Unfortunately, just the basket and the empty cooler weighed 22 pounds, and I would have had to push a 60-pound load. In the end, I wound up following another friend's suggestion of dispensing with the cooler and carrying a jug of water on the rear axle.
Too much weight; back to the drawing board.
The jogger solved one problem, but created two others. Now that I needed my hands to push the jogger, I couldn't hold an umbrella. I certainly wasn't too keen on walking without one. All the reported temperatures are taken in shade and a person in direct sunlight would feel as if the temperature was about 15°F higher. Luckily, I was able to rig up a way to hold my umbrella in my day pack. The other problem with the jogger was the possibility of a flat tire. This required me to carry a pump, spare tubes and tools.