You raise it back up...
That's what coilovers are for
Its not as serious as you make it sound though, unless it snows A LOT you should be fine. If its that much snow, you shoudnt be driving a car like that anyways, thats SUV time. Pothole? Avoid it, there arent potholes EVERYWHERE like some people make it seem like. I live in NYC, when I had a lowered car, id move my steering wheel 2 inches and avoid it. Speed bumps arent made to destroy lowered cars, its meant to slow you down. So slow down.
I dont know about SLAMMED cars though, they look nice but THOSE are impractical.