Anybody’s guess without looking at it. Your best shot is to put a drain tray under the car, fill it up with tranny fluid and start it up to determine the leak location and leak rate. Check first to make sure the tranny isn’t full of water, if it is you’ll need to get it drained, flushed and new tranny fluid along with a new rad / oil cooler. The tranny may be compromised if it’s been driven any distance full of water.
If it’s just a leak but a heavy one and you can’t fix the leak in situ, get the car trailered to a tranny shop, don’t try and drive it.