Sarah Thomas - Flathead Lake

Somers to Polson

27.6 miles

13 hours, 39 minutes on July 3, 2015

Observed and documented by Ryan Willis

First unassisted Flathead Lake length swim


  • Name: Sarah Thomas
  • Age on swim date: 33
  • Nationality: United States
  • Resides: Conifer, Colorado

Swim Route

Lengthwise crossing of Flathead Lake (Montana, USA) – Somers to Polson.

Route Definition

Minimum Repeatable Route Distance: 44.5 km (27.65 miles)

Location Latitude Longitude
Somers 48.077061 -114.23599
Angel Point 47.985125 -114.166832
Black Point 47.784788 -114.125805
The Narrows 47.769849 -114.128809
The Narrows 47.767022 -114.130354
Polson Bay Bridge 47.694584 -114.166124
Riverside Park 47.694151 -114.165599

Support Personnel

  • Pilot 1: Mark Johnston
  • Pilot 2: Greg McCormick (from 7:45am)
  • Observer: Ryan Willis
  • Paddler: Scott Olson

Swim Data

Note: This was a simultaneous solo swim with Craig Lenning (documented separately).

  • Start: July 3, 2015, 03:43 (Mountain Daylight Time)
  • Finish: July 3, 2015, 17:22
  • Elapsed: 13 hours, 39 minutes

First unassisted lengthwise crossing of Flathead Lake.

Summary of Conditions

  • Water Temp: 70-71F at start, to 75F at end
  • Air Temp: 55F at start to 95F mid-afternoon
  • Wind Speed: calm at start to 10mph mid-afternoon

Observer Log


by Sarah Thomas

Craig and I were pretty close together the first half of the swim. Everything was really pleasant and great for about 6 hours. Then, the wind picked up a little and it started to gradually get hotter and hotter.

After we went through the Narrows and were swimming through Polson Bay it was miserable for both of us- water was hot, air was hot, there were tons of boats (I think we only saw one or two during the first 2/3 of the swim), and it was pretty choppy.

I know it was the final stretch through the Bay that I picked up my time on Craig- we weren’t very far ahead most of the swim, but the heat was really getting to him at the end. (Did I say it was awful yet?) I remember Ryan commenting about how easy of a swim it was for the first half.

Then, everyone started to melt. Scott got sunscreen in his eyes and had to get off the kayak to deal with that, Ryan’s feet/legs were burning so badly that I could see it while I was swimming and told him to cover his legs with the lifejacket. Greg jumped off the boat and into the water to cool off during one of my feeds. There were also about a million kids playing at the park/boat ramp when we finished. And someone stole Scott’s $400 kayak paddle while we were waiting for Craig to finish.


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