See the 1941 Ruby Creek incident, John Green Report # 1000009 (BC is in North America)
"The Chapman home was on a small Indian reserve beside the Fraser River, only a few hundred yards from the mountain foot. A deputy sheriff, Joe Dunn from Bellingham, made a cast of a track. It was later lost but a tracing of it survives."
Also in the John Green database is a report from 1949 in Stevens County Washington. (John Green 1000686 - not posted on BFF)
"Ben Thompson said he saw a very large sasquatch at Leadpoint, watching it through a scope at 800 to 1000 yards, and tried to put his bear dogs on its trail, but they declined. It was heading West over the mountain towards Northport. Said tracks were of cripple-foot, but was very graceful. Said he had cast."
Bob Titmus cast a track in BC in 1961, but the cast was lost when his boat burned. (John Green 1000047 - not posted on BFF)
"Bob Titmus had anchored his boat in the shelter of an islet in Kitasu Bay during a storm and saw tracks on the beach. He had to strip and swim ashore to look at them. They started at the tideline and went into the brush, where he could not follow at the time. Later he was unable to find where the tracks re-entered the water, presumably over solid rock. The cast was destroyed the following year when his boat burned."
Besides those 3, there were a few more in the 50's