Can the liner and shell be worn separately?

Yes. The insulated liner zips out and can be worn on its own as a light jacket, and the shell works alone as a rain and wind layer. The liner alone is not waterproof.

Is it warm enough for skiing?

With the liner zipped in it handles typical resort winter days, especially with a base layer. On very cold days add a fleece; on warm spring days wear the shell alone with the pit zips open.

How does it fit compared with other Columbia jackets?

It runs large and roomy to layer underneath, and the tall sizes add sleeve and body length. Many buyers go down a size for a closer fit.

Is the hood helmet-compatible?

Yes. The hood is sized to fit over a ski helmet and adjusts with drawcords, and it can be stowed or removed depending on the model year.

What is the difference from the Whirlibird IV?

The V is the newer generation with an updated shell fabric and hood design. The core three-in-one layout, powder skirt and pit zips carry over, so the older model is still a reasonable alternative if you find it.

Is it good for everyday city wear?

Yes, in cold wet weather. It is waterproof and warm, but it is bulkier and more technical-looking than a city coat, so it suits commuters more than dressy occasions.