A few quick facts:
– Icing is worse between 0°C and -35°C, theoretically supercooled water droplets does not form under -35°C. Although, here we have a MCC (Mesoscale Convective Complex) which is a whole bunch of thunderstorm clusters so intense and vast, which such strong convective currents (and relatively warm air on that 1st of june 2009) that such supercooled droplets were there at FL350.
– If anyone didn’t remember those pitot probes were faulty