Not great photos and I'm personally not sure of what features make this a Hoary and not a Common, but many knowledgeable local birders have ID'd this unusual visitor, so I'm going on their expertise.
Small clump beside the walkway, southwest of the skating trail.
two individuals observed, in second photo
observed with annebarbour1
with husband Brian and Ginny Moore. Two birds that looked like juvenals. Same birds as posted by Ginny at https://inaturalist.ca/observations/179673401