Seel established herself as a leading female competitor in enduro racing before turning to the high-profile challenges that defined her public reputation. Enduro racing, which demands sustained mechanical sympathy and navigation across varied off-road terrain, provided the technical foundation for her later exploits. She became a regular participant in the Paris-Dakar Rally, one of the most arduous endurance events in motorsport, covering thousands of kilometres across desert, mountain, and savannah terrain.
In 2003 Seel rode a 20-year-old Honda XL250 fitted with ice tyres to an altitude of 5,305 metres (17,405 feet), reaching the Mount Everest base camp and breaking the existing unofficial altitude record for motorcycle riding by more than 50 metres (160 feet). The choice of an older machine was not optional: the Nepalese government had banned the importation of new motorcycles into Nepal, restricting Seel to locally available or previously imported equipment. The ice tyres were fitted to cope with the frozen terrain encountered at high altitude on the approach to base camp. This record was subsequently broken in 2011 by British rider Tamsin Jones, who, together with her partner Craig Bounds, reached 5,359 metres.
Seel became the first woman to compete in the TSCO Vegas to Reno desert motorcycle race, a 500-mile (approximately 800 km) off-road event held across the Nevada desert. In that race she finished as the fifth-highest-placed amateur, a result recognised as part of the achievements for which she received the Swedish Adventurer of the Year award in 2005.
She also became the FIM's first Ride Green woman eco-enduro champion, winning a race for electric motorcycles that was designed to promote environmentally responsible motorsport. This early engagement with electric competition presaged her entry into the emerging electric grand prix scene.
In 2010 Seel competed in the TTXGP, billed as the world's first electric grand prix, held at Snetterton Motor Racing Circuit in the United Kingdom. She rode the Morris Motorcycles Racing team's Mavizen TTX02 machine, a purpose-built electric race bike, placing her among the first generation of professional riders to contest a fully electric motorcycle grand prix.
During the 2010 Dakar Rally, which by that point had been relocated from Africa to South America, Seel crashed into a tomb measuring approximately 16 feet (4.9 metres) deep. Despite the severity of the incident she continued and completed the rally, underlining the physical resilience that had characterised her career throughout.
Seel's career crosses several distinct strands of motorsport history: the tradition of female endurance racers competing on equal terms in events such as the Paris-Dakar Rally, the adventure-motorcycling record-attempt culture that emerged in the late 1990s and early 2000s, and the first wave of competitive electric motorcycle racing. Her Everest base camp altitude record attracted widespread media attention and the Swedish Adventurer of the Year recognition reflected the degree to which her achievements were understood to extend beyond sport into exploration.