Good afternoon everyone,
Now that the big freeze is over, the nature of the phone calls I have been getting has changed: now comes the fallout from all the rain, snow, and thawing frozen earth. Some folks have already experienced small or moderate amounts of flooding in basements, garages, or other parts of the house.
I believe the worst of this phase of the storm / warm snap is still to come tonight through the weekend. With particularly heavy rain on Friday and Saturday, coupled with the potential for a hard re-freeze Sunday into Monday, there exists a high potential for flooding. In addition to basements, properties situated on hillside or low-lying areas are vulnerable, even if there is not a prior history of flooding at those properties.
This problem is occuring because the ground has recently had a hard, deep freeze and the ability for the ground to absorb the thawing snow and the new rain is very limited. The soil frequently remains frozen, even though the surface appears soft, thawed, or even muddy. The frozen sub-surface will stop water from seeping to the ground as it ordinarily would. Snow cover will act like an artificial 'ground surface', creating unusual drainage paths for the rain and thaw.
Here is the advice I am sharing with our clients regarding preparations for this weekend:
If you still have accumulated snow against or near the house, remove it. Do not plan on having the rain wash away the snow. While it will eventually occur, the initial rain may run down the piles and toward your house. If any snow remains when the re-freeze occurs, you will have formed a sort of 'funnel' directing subsequent rains towards the structure.
If you have shaded areas that still have snow coverage with slopes to the house, clear a small path in the snow to a lower point away from the house. While most of the snow from the recent storm is melted away where sun has been present, shaded areas (between buildings for example) may have a continuous snow surface. Clear a small 'trench' in the snow to provide a means for the water to have an alternative means to drain. This can be accomplished by simply walking and stomping a path in the snow.
Check window well covers. The winds associated with the recent storm have displaced many covers. If you have not been outside to inspect the window wells since the cold snap, covers may be missing or dislodged.
Check driveway and exterior stairwell drains for snow or debris accumulation and clear if necessary. These drains will only protect you if they are free of blockage.
Consider a high water alarm. Basic battery powered water alarms to detect flooding conditions around water heaters, furnaces, and similar appliances are inexpensive and are available at Home Depot, Lowes, and other home improvement stores for around $25-$35. By placing the device inside the house near your exterior basement door, window well, or other likely point of water intrusion, you can be warned early in the seeping flooding cycle and minimize damage to your home and personal effects.