Biasca is a town of the district of Riviera in the canton of Ticino in Switzerland. Biasca is first mentioned in 830 as Aviasca in the Liber v…Biasca is a town of the district of Riviera in the canton of Ticino in Switzerland. Biasca is first mentioned in 830 as Aviasca in the Liber viventium of Pfäfers Abbey. In 1119 it was mentioned as Abiasca.