Buy a ski helmet!!!! Biking helmets are different to ski helmets and are not as safe.
If you want to, you can take out the earflaps. Go to a local shop, look what they got there, try out helmets you like and if the helmet fits you, buy it.
All ski helmets have to conform to safety regulations, so it really comes down to which you prefer. It's important you find one which fits you and interfaces well with your helmet/goggle combo. Most helmets have detachable ear pads, so just rip 'em out if you don't want them there.