LED's won't melt the snow cause they run cooler so no need for a million watts.
A pair of LED reversing lights will work wonders.
Check the wattage of the existing globes.
While not exactly true, for all practical purposes a Watt is a Watt is a Watt.
So if you have 2 x 25 Watt globes then you have 50 Watts to play with.
If you want more light, 4 CREE Leds in series ( 3 volts a piece ).
Lots of car & motorcycle plug in LED globes available, you should even be able to run AC ones ( fridge lamps ).