Now in its ninth year, the Arrowhead 135 Ultramarathon is one of the most challenging in the nation.
It is organized by Dave and Mary Pramann, with the help of numerous volunteers.
Entrants depart the Arrowhead State Trail in International Falls, MN, known to many as "America's Icebox", either skiing, running or cycling in sub-zero temperatures that challenge even the most seasoned athletes. The course winds south and ends near Tower, MN.
Mary's blog on the Arrowhead 135 home page is both informative and entertaining. However, she and Dave take this event VERY seriously.
There are stringent entry qualifications and race rules, and other precautions taken to help ensure the safety of the men and women who enter. (It sold out back in October.)
While the Arrowhead 135 itself supports the Warrior Foundation, some participants also individually raise funds for the SOWF.
Arrowhead 135 event website and Facebook page
2011 video of the trail
Steve Tannen fundraising page