At aid station #2 we turned onto the Pacific Crest Trail, and followed the smooth single-track through a serene Jeffrey pine forest on the north slopes of Delamar Mountain. It was a little chilly and breezy at 7800′, and the strong June sun felt good on my bare arms. I was at about mile 9 of the Holcomb Valley 33 Mile Trail Run and all was good. The subtle vanilla scent of the pines wafted through the trees, and here and there bright yellow blossoms of western wallflower seemed to mark the way.

Rounding a corner, a pine framed image of Big Bear Lake and snow covered San Gorgonio popped into view. Behind me, a runner exclaimed, “Gorgeous!” As she passed, she commented, “This is my favorite race!” And I can see why. Not only is the race well organized, with great aid stations and super helpful volunteers, it challenges the runner with a unique mix of terrain and altitude.

Some stretches of the course are smooth and fast, some technical, and some downright gnarly. Most of the hills are not steep — at least by sea level standards — and the total elevation gain/loss is only about 3600′. But the gotcha is this: the course has the highest average elevation of any 50K race in Southern California, including the Bishop High Sierra 50K! Nearly 30 miles of the course is above 7000′, and the altitude has an unavoidable effect on performance, particularly for the unacclimatized, middle-of-the-pack runner.

How much of an effect? There is an often referenced chart in the book the Daniels Running Formula that can be used to estimate how much slower we will run at a particular altitude. Using an online running calculator based on the chart, we can project that a runner that does a 33 mile course at an elevation of 1000′ in 6.5 hours would take about 7 hours at 7500′ — assuming the runner is fully acclimatized! In the book, Daniels says that the increase in time could be as much as double for an unacclimatized runner. So 33 miles in 6.5 hours near sea level might turn into 7.5 hours at 7500′.

At altitude, elite runners have an advantage — even more of an advantage than they have at lower elevations. Because of the reduction in air density and drag, running at altitude at their faster pace is more efficient than near sea level. This partially offsets the loss in aerobic power that results from the reduction in atmospheric pressure. Again using the Runworks calculator, a runner that runs 33 miles in 4 hours at 1000′, would be projected to run about 4:18:00 at 7500′.

Apparently immune to the altitude, and flowing over the rocky sections of trail like the wind, Michelle Barton and Jorge Pacheco set new records on the Holcomb course this year. Michelle Barton flew through the 33 mile course in 4:56:21 (8:59 min/mi), and Jorge Pacheco cranked out an amazing 4:13:44 (7:41 min/mi). To put those times in perspective, this year the median time (half the runners above, half below) was  about 7:36:00.

Here is a Cesium ion interactive view of my GPS trace of the 33.1 mile course, and an elevation profile generated in SportTracks. Distances specified are based on the trace, and were calculated in SportTracks. During the race the only segment that seemed significantly longer than expected was from aid station #4 to aid station #5. Part of the reason is it was a tough leg, and has some very rocky stretches. But it also looks like the segment was about 7 miles long, rather than the expected 5.9 miles.

Many thanks to Pam and Gary Kalina, Bear Valley Search & Rescue, the sponsors, and all the volunteers for a great race! All the results can be found on the Holcomb Valley Trail Runs web site.