In this video BMW 3 Series (E90) in snow without snow chains. This car is not xDrive. Only rear wheel drive!
Smart system DTC does a great job in snow:
Dynamic Traction Control (DTC).
Dynamic Traction Control (DTC) allows more wheel slip and thus a more dynamic driving style with higher wheel traction and DSC controlling stability. A small amount of spin on the drive wheels improves traction when pulling off from a standstill in snow or on loose terrain.
Dynamic Traction Control (DTC) is a sub-function of the Dynamic Stability Control (DSC) system that can be turned on and off. DTC has two major roles: to regulate traction and to enable sports-style driving while providing active stability control.
When the drive wheels start losing traction the DSC automatically begins stabilisation measures. The Dynamic Stability Control system curbs the engine output and stops slip on the wheels. In exceptional situations, however, a small amount of wheel slip can be an advantage.
When driving in deep snow, slush or on loose terrain a small amount of wheel spin improves traction. For these occasions, as well as those when the drivers want a sportier driving style, the DTC can be activated by pressing a button and this allows more slip and reduces the DSC’s curbing of the engine. The result: better traction and more thrust.
The DTC also makes driving on snow and ice-free roads more dynamic. When activated, the DTC allows sporty drivers more room to manoeuvre around curves than the Dynamic Stability Control and even permits controlled drifts. The driver retains complete control over the vehicle in every situation and the Dynamic Stability Control’s stabilising measures remain active even when the DTC is activated.