AID STATION MILEAGES

bear 100 2008 mileage chart

Is it really 100 miles? As you can imagine,  measuring a 100-mile course is very difficult.  Phil Lowry has measured several courses with an accurate survey-grade GPS, and this course is no exception.  He also checked the course against 1-foot resolution photographs of the entire course.  These photos can be imported into software with very precise surveying and measuring tools. These include correction for ups and downs, which adds a bit of distance.  

If you are really bothered by being short a half mile, remember that there is no accounting for distances travelled in aid stations.   Now, if at each aid station you take 50 extra steps off the plotted course, averaging two feet per step, you get an extra quarter mile.  We're sure you'll get the other quarter mile somewhere along the way ;-).  All kidding aside, when measuring a course like this, getting within a mile is within the margin of error (1%), based on measurer and satellite variations.  We are as close to 100 miles as practicable (without just making it up).

If you have questions about trail mapping, distance measuring, or the methods and tools described here, email Phil at phil@phillowry.com.

Elevation Gain Calculations

Elevation gain and loss--the ups and downs of the race--can be measured two ways.  One way is to take an altimeter watch and use its measurements while running the course you want to measure.  But these watches usually will only detect gains of over 3 meters (ten feet), and are very much affected by humidity, weather, and temperature.  The other solution is to get a GPS track and then plot that over a computer elevation model of the Earth's surface.  This can be very accurate, but because it detects every little change it can be jarring when you see the results.  For example, an altimeter watch says that the total gain at the Wasatch 100 is 24,000 feet, but the computer says it has a gain of 32,000 feet!  Both are "correct"--they just use different methods to calculate gain and loss, and you have to remember that the watch will be increasingly inaccurate the as the temperature climbs above 40 degrees F.  The key is to compare apples to apples.  You can't compare a computer-generated profile of one race against a watch-generated profile of another.  Wasatch says that they have nearly 27,000' feet of gain, which is close to a correct altimeter calculation.  That is about 85% of a computer-generated profile.  So, Phil did the same for the Bear.  The computer says it has 26,500' of gain, so the hard number is about 22,500' of gain.