The runways at KEF are actually 11 and 20. Winds of 150-160(M) at 50-70 are not uncommon during winter, right between the runways. It can be a real toss up which one to use. In addition the windsensors are somewhat badly placed as buildings appear to create disturbances affecting them, and also aircraft on short finals.
It has served me well in windy and gusty situations all over the world, to keep the FMC on PROG II (757/767) and take a peek at the crosswind occasionally, it will normally give you a fairly stable wind indication to base your descision whether to land or not in limiting situations.