Cascade Super Series Marathon Race Info

Date: 9/29/18

Location: Snoqualmie Pass, WA to Rattlesnake Lake

Start Time: 8:00am

Avg Temps (f): 57/42

Time Limit: 7 hours

Summary: A popular race outside of Seattle, known for its mainly downhill course and crushed gravel footing on a point to point course, this course is PR friendly, and there are several race companies that put on races on this course, this one hosting races in late June and late September. The course starts at an elevation of 2,550′ at Hyak Parking lot at Snoqualmie Pass, first makes a 5 mile out and back on the Iron Horse Trail (heading away from Seattle), and then proceeds through a 2.4 mile tunnel, after which it gently descends roughly 1500 feet all the way to the finish at Rattlesnake Lake.

Lessons Learned from Race Reports

  • Runners are given a flashlight before they enter the 2.5 mile tunnel, which they can keep or drop off at the other end. If a runner uses their own headlamp, you are required to have it the entire time
  • Be sure to review the information on parking and shuttles, as the start and finish are in different locations and there are lots of places you can’t park
  • First 5 miles are an out and back and mostly flat with tiny hills, then you enter the 2.4 mile tunnel, then it’s downhill over the remaining 17.5 miles of the course
  • Your watch likely won’t work in the tunnel, so don’t believe the splits
  • The tunnel is a little disorienting, so plan on it feeling a bit odd to run through, then get your bearings on the other side
  • There are puddles in the tunnel, so if you’re running with a group, you’ll likely step in them before you see them
  • It gets warmer as you go from the start to the finish, so while you might be chilly at the start, it will get warmer as you head downhill to Rattlesnake
  • Lots of shade throughout on the course, with bridge crossings being more exposed
  • With aid stations every 2-3 miles, be sure to drink something if you want, because if you skip one, it’s a long way between 2 aid stations.
  • Not many bathrooms along the course since the aid stations are remote; best chance for one is around mile 18
  • The trail is smooth enough for road shoes, but there are some sections with some bigger rocks, so if you have light trail shoes, those work well too
  • Some runners wear gaitors so they avoid rocks getting into their shoes
  • Trail is mainly double track, so you run on either side of it, but not in the middle, where there are more rocks. Makes it a little harder to run the tangents and keep the distance as close to the measured course as possible
  • Only small uphill is at mile 13 and it happens quickly, short and slightly steep


Total gain/loss: 10/1500

Total climbs: None

Course Map/Elevation profile


Aid stations

Total aid stations: 9

Furthest distance apart: 2.5 miles

Locations: Mile 2.5, 5.2, 7.7, 10.4, 13.1, 15.8, 18.5, 21.5, 23.9
What’s available: Water and electrolyte drink at every aid station; gels are given out at miles 13.1, 18.5, 23.9

Crew access

At the start and as runners come back from the first out and back, around mile 5, and at the finish (note, different locations since it’s point to point), and possibly mile 18.5, a good spot to access the Iron Horse Trail.

Race qualifiers


Race Reports

Tess C’s 2018 September Report


Strava activities and GPX files


Race Website