Looks like a mountain ash to my amateur eyes.

Leaves don't look right for mountain ash. Maybe red elder?

I would agree with red elder

Don,

Thank you. I think you're right. I cut the stem and it's not woody. The leaves are opposite. The fruit looks about the same.

It is growing in the Bow River valley in Calgary and would appear to be a native plant.

Here is a link that might be useful: Sambucus racemosa