Williamson, 43, a visually-impaired skier, skied for 17 years with the national team, piling up numerous accomplishments.
A bronze medallist in slalom at the Sochi 2014 Paralympic Games, along with his guide Nick Brush, overcame injuries that plagued him late in his career.
Williamson competed for 17 seasons, which makes him the longest standing member of the Canadian Para Alpine team, as well as the most decorated competitor earning gold, silver and two bronze medals at the Paralympic Games, 13 IPC Alpine Skiing World Championships medals, eight IPC Crystal Globes (14 disciplines titles) and 105 IPC World Cup podiums, 56 of which were victories.
Hallat, who turns 31 later this month, had his right leg amputated due to Ewing's sarcoma before his 10th birthday. He was a member of the Canadian Para Alpine ski team for 13 years and was a bronze medallist at the 2015 IPC alpine skiing world championships.
Both Williamson and Hallat last competed at the Canadian national championships in March at Mont Ste. Anne, Que. Hallat was third in his final race.