Solar panel generates electricity even being covered with snow as white snow transmits the light well enough. In fact, in winter, on a clear and frosty day module efficiency may even rise because of light reflection from snow, especially in February and March.
Moreover, in northern countries, such as Canada, Russia and Norway, solar modules are mounted at a wide angle to horizon or even vertically on walls to prevent snow accumulation, which may badly impact power generation.
However from November to January, when the weather is mostly cloudy, the efficiency of solar panels may decrease by 5 times. Therefore we recommend to use hybrid systems, which allow to produce electricity also using wind energy and to accumulate it in batteries. A 1-2 kW wind turbine will significantly improve your energy autonomy and there will be no need to worry about blackouts.