I spun my IS earlier this year when we had the snow... Going down the M2 at 4am going home from work, nothing about, then a lorry started sliding towards me, swerverd to get round it & back end started to drift out, corrected it, got past said lorry, turned to get back on the clear bit of road & the back end went again, a lot faster this time, went round & round about 3 or 4 times.
Moved car to hard shoulder (roughly), managed not to hit anything at all so emptied undies & carried on with my journey... Extremely carefuly!
TC is a waste of time in the snow, it only works if theres somewhere to get traction.
Stuart