Please Help! Ground water leaking into heating ducts

We live in Maine and are experiencing heavy rain right now. We have noticed that ground water is coming into our heating ducts which are in the slab. When we turned our furnace on we hear bubbling water. We checked the ducts and some of them have 3 to 5 inches of water in them. How do we go about fixing this. Currently we are not running the furnace as we don't want to ruin it, and have started the wood stove back up (40 degrees is too hot for a stove, but our only choice).

Hoping for some quick advice. It will be another month or so before we can dig up around the slab as we still have frost and snow on the ground.

water

Get a pump, such as a Little Giant, with a garden hose outlet adapter. Drop it into the ducts and pump the water out.