New washer is in basement; we have a hose going up to the long hose that goes down and outside.does not go to sewer but a leach field. Could line be frozen? It's never happened before this...

If the ground in the area of the leach field is frozen that is most likely the problem.

Washer discharge hoses should be air gapped and not directly connected to an outside drain, particularly underground. You are getting backwash. Remove the washer hose at the outside connection and place it in a 5 gallon bucket. Put some water in the washer and then cycle to a drain position. Does the water come out of the pump and then stop? If so, you could have a frozen line or a blocked line from washer debris. Lint from the washer goes into the piping or leachfield and slowly blocks it. Is your leachfield above the basement foundation? Most leachfields are set below the foundation to prevent waste from possibly getting back into the basement through a wall crack. Do you have a sink near the washer? You could put the washer outflow into the sink after running it through a lint screen. If you are really out in the country, you could let the grey water(washer discharge) run into a small pit or dry well.