A useful information site is http://www.ready.gov/floods.
Protracted or intense rains can cause flooding and earth cave-outs. Each homeowner should assess where their property might be vulnerable. As our area continues to develop, this is becoming more critical as water passes through one property to another.
Preparing & Responding
Inspect your property and become aware of how water flows across it. This may change because of new adjacent home construction or road work. You should take the initiative to install pipe, ditches, or other appropriate measures to protect your home from storm runoff, and also to shepherd the water so that it does not threaten neighbors. For example, if ditch water from a road empties onto your lot, you may need to install piping to conduct this water through your lot to a safe drainage point.
Protect your house with well-engineered retaining walls, with adequate drain pipe behind them.
Monitor your property during heavy rains. Flowing bodies of water can be deceptively powerful and deadly. Mudflows and landslides are even more powerful and deadly, and they can occur with little or no warning.
Residents living on, near, or below slope areas should be familiar with the awareness, preparedness, and response information available on the following two websites: