A homeowner comes downstairs in the morning to find water running down the inside his front door and walls. Another, who has experienced no water problems during 20 years in his house, suddenly finds himself roll ing up rugs and taking down drapes to save them from soaking. Six weeks after moving into their dream home, a young couple discover that it is raining from several first-floor ceilings.

These are just three out of hundreds of area households presently trying to cope with a very unpleasant weather phenomenon -- the ice dam.

Ice dams begin with a heavy snow buildup on the roof. Then a series of freezing -- melting cycles pack the gutters and eaves with ice, forming a dam to collect succeeding layers. Eventually, this works its way up under the shingles and finally to where the roof meets the walls. Escaping heat from the interior now melts the ice next to the shingles and the water runs back up, then down walls (inside and out) and through ceilings.

Not all houses have the problem. For one, steep, sloping roofs restrict backup. Some houses have no gutters, so the dams may not form in the first place. The old-fashioned "half-round" gutter, which hangs from the roof edge rather than being directly attached, is less likely to create a dam.

Wide-roof overhangs are good, since the water buildup has to run back further to get to the house walls. The soffit, (or underside) of the overhand will receive water, however. If interiorgrade plywood was improperly used for the soffit, it will eventually warp and delaminate.

The soffit should have several ventilation openings, the closer to the walls the better, to prevent water from freezing. These holes are for attic ventialation but may serve as weep holes and allow the water to escape.

Much also depends on how high the finished exterior walls run above the soffit overhang, and how tightly the wall was put together in the first place. In this regard a masonry wall would be better than a brick veneer, which generally terminates at the overhang.

Some roofers provide partial defense against ice dams when the roof is first put on the house frame.A metal "eave drip ledge" helps; so does a sheet of roll roofing or metal, about three feet wide under the lower shingle courses.

One can even heat the areas where dams form. Thermal wiring can be temporarily or permanently installed in gutters and downspouts and/or under the lower three or four shingle courses, then heated, when ice threatens.

What can you do now that the dam has already been built? The options are limited, but here are some suggestions:

Wherever possible, get at the dams with a hammer and icepick or old screwdriver and remove as much ice as you can.

Sweep snow off the lower lower edge of the roof.

In drastic situations, you may consider temporary removal of some gutters.

Drill or cut weep holes in the soffit if there are none. At the same time you will be improving attic ventilation for next summer.

Lay a thermal wire on top of the. iced gutter. One resourceful homeowner had partial success with a hairdryer and iron.

Inside, if ceilings are dripping badly, punch small holes in the plaster to let the water out quickly. Then catch it in buckets below. Repairing these holes could prove much less costly than allowing the water to collect and do more widespread, serious damage.

Beyond those methods, homeowners must wait it out, wiping up the water as soon as as often as possible.