The account is understood to have been won after a three-way pitch. Radiator MD Gaby Jesson said US-based Columbia had been expanding its product range and distribution in the UK to challenge established markets.
While best known for its ski-wear, the company also enjoyed a 'good outdoor retail base' for its rock climbing and hiking clothing, according to Jesson.
She said the key challenge would be to build Columbia ski clothing's association with snowboarding, and particularly with freestyle ski-ing - off-piste activities where points are awarded to the most dangerous stunts.
Jesson said freestyle ski-ing was taking over from snowboarding as the 'coolest' winter sports activity and was seen as more 'dangerous and exciting' than its rival.