Actually this car wasn’t frozen accidently. Its owner got it frozen for winter intentionally. Reasons are various. First, if the car is used the whole winter, it could work a short period of time only. Second, to have a warm, heated garage is relatively expensive. Such a garage in downtown may cost approx. 1,000,000 rubles (~33,000USD). A month heated garage rent cost ~300 USD. Third, a car consumes in cold weather more fuel than in summer, and one litre is sold here at the price of ~1 USD
But keeping a car frozen might be risky. In the course of the long winter, from the mid October till the end of April, anything unpleasant can happen to a loved vehicle. Like flooding as a result of water supply pipes leakage.