As of October 2019, the FAA has used mu values to describe braking conditions In Europe this differs from the above reference.
In a crosswind landing, the pilot tacks into wind to make allowances for the sideways force that is being applied to the aircraft (also known as using a crab angle).
Just before or upon initial ground contact, the pilot must re-align the fuselage to zero the drift angle (i.e. correct it to parallel with the runway's centreline).
As the wheels make contact with the runway surface there are a lot of side forces and torsion placed on the tyres due to them countering the weathervane effect which continues to try to act upon the aircraft.
If however the surface friction is diminished because of contamination then this may upset the balance of forces resulting in insufficient directional control to keep the aircraft on the runway.
Pilots may receive this data through a "Snowtam runway state decoder" which forms an appendix to the internationally recognised METAR (METeorological Aerodrome Report).