The BMW iX isn't the only flagship electric SUV undergoing winter testing, as Mercedes has been caught by our spy photographers putting the upcoming EQS SUV through its paces in the snow. Testing in these conditions will enable Mercedes to evaluate how the electric components cope in cold temperature and make any necessary changes ahead of production.

Effectively, this is the electric equivalent of the Mercedes GLS and the SUV sibling for the EQS Sedan previewed by the Vision EQS. While this is our first look at the EQS SUV undergoing cold-weather testing, the prototype is wrapped up warm in a thick camouflage.

We can see that the EQS SUV will be smaller than the GLS and Mercedes Vision EQS and design cues from the Vision EQS such as the slim headlights flowing into the closed grille appear to be carrying over.

Whereas the EQC is based on the same platform as the combustion-powered GLC, both EQS models will ride on Mercedes' new Electric Vehicle Architecture built specifically for EVs to optimize the battery packaging. We don't have any new photos of the cabin to share, but previous spy shots have shown the cabin will borrow technology from the new S-Class including a massive portrait screen displaying the MBUX infotainment system and a large digital display.

Mercedes has already confirmed the EQS sedan will have an EPA-rated range of 435 miles on a single charge, but the larger SUV will inevitably have a lower range. The German automaker hasn't confirmed the performance specifications yet, but the Vision EQS utilized a dual electric motor setup with combined outputs of 469 horsepower and 560 lb-ft of torque.

The EQS SUV is expected to go on sale in 2022 and will be joined by the smaller EQE SUV as Mercedes prepares to expand its electric EQ family to ten models by the end of 2022.