METEOROLOGIST JEFF HABY
One of the greatest risks from storms is flooding. When a flood occurs, water rises at locations that are occupied by buildings, roads and
where people are located. It is important to make people aware of the relative flood risk of locations such as at the locations of homes,
parks, businesses and roadways. Many people are willing to accept the risk, especially if the land is valuable and/or the yearly risk is
low. Flood risk is often defined as the probability of a particular flood height occurring in a given year. One common parameter is the
100year flood. To be a 100 year flood, there is a 1% chance of a location getting a particular flood height in a given year. A 10 year
flood would have a 10% chance of occurring each year. The larger the number of particular flood heights expected in a 10 or 100 year
period, then the greater the flood risk. Since it is a probability, it is not a guarantee of how many floods will occur every 10 or
100 years but rather is a guide for the typical number of floods that can be expected or the percent chance of a particular flood
height each year (the actual flood heights or percentage of years with a particular flood height can end up being higher or lower
than the theoretical value). Locations that are typically at greater flood risk are along the coast, in low lying area, near
rivers/streams and where water ponds since it can only slowly drain away. It is important to understand the flood risk of a
location since it determines insurance rates and the risks to property and life.


