Flood Risk and Vulnerability Analysis Project - Atlantic Climate ...

fresh water from the Arctic south along the continental shelf and slope of Labrador and
Newfoundland. The Gulf Stream brings warm and salty water north from the Gulf of Mexico
along the continental slope of North America. It veers to the northeast away from the continent
at Cape Hatteras and flows eastward just south of the Grand Banks, occasionally moving north
onto their southern edge. The presence of the air masses over the two currents, moist and cold
over the Labrador Current, moist and warm over the Gulf Stream, directly affects the
temperature, precipitation and formation of fog, especially on the eastern coastal region of the
island of Newfoundland.
The ocean currents which exert a major influence on Newfoundland and Labrador climate are
not expected to change significantly as a result of global warming over this century. The oceanatmosphere
oscillations that are responsible, to some extent, for the observed decadal (and
longer) cycles in warmer and colder periods and periods with greater tropical storm intensity,
continue through to the end of this century, if not beyond. Their periodicity and intensity may
change somewhat over the coming decades and tracking those may help to predict climate
anomalies in particular years or series of years in the future. But because these planetary scale
general circulation features are in all likelihood well handled by global climate models, the
gradual upward trends in temperature and precipitation seen out to 2050 and 2080 likely
capture the long term effects of the small changes in these large ocean currents and oscillations
Worst case scenarios are intense phenomena that may occur in isolation or in combination with
other events or circumstances that could lead to extreme water levels and hence flooding
conditions. A preliminary, largely qualitative, assessment of scenarios that could lead to extreme
flooding in parts of Newfoundland and Labrador was completed focusing on winter rain,
Weather bombs, hurricanes and tropical storms, and severe summer weather. While these
phenomena are considered rare, most of these events have occurred in the past and are likely
to occur again.
Assessing the Need for New or Updated Flood Risk Mapping
The objective of this project task was the identification of communities vulnerable to flooding
that should be considered for new or updated flood risk mapping studies. This assessment was
founded on the updated Flood Events Inventory, the re-assessment of Flood Risk Maps, a
detailed review of the technical components comprising the existing flood plain maps and
linkage of a variety of datasets relevant to flood risk assessment in the Province. The definition
of communities was based on the Local Government Profile (LGP) number dataset.
A decision matrix was developed outlining community ranking based on the prioritization
parameters outlined in the table below. One additional consideration was integrated into the
analysis at this stage, namely, the hierarchy of prioritization parameters. In other words, the
concept that some of the parameters used for prioritization are more important for the analysis
than others. In review of the parameters, some, such as number of flood events reported in a
community or reported flood damages, are documented evidence of flood risk. These
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