In reply to Flashman38:
> It`s difficult to heat up Polartec Alpha when only 45g/m weight.
> For the runners only surely.
I guess you haven't really used one...
The two jackets I have are more than adequate for -15 to -20 deg C ice climbs fests with a thin wool under layer (and if needed water & wind repellent top layer). Sure a belay jacket is handy at those temps... but that's what everyone has... warmer temps (think around -5 deg C), the alpha is enough.