This is definitely Amanita muscari (highly poisonous!). There are a few populations of it on the west side of Vancouver. As for the proliferation of mushrooms last year, it is the result of steady rain and higher moisture at the right time of year: spring and fall, especially in September. Usually we have a drier September than this past one, and last spring and summer were also considerably more wet, with lower temperatures in summer than the previous year. The UBC Herbarium always welcomes plant or fungi identification questions from the public. Phone: 604-822-3344 or email ubc@interchange.ubc.ca