58
Lesson N °9.
Coastal storms :
Storms represent nature in one of its most energetic and violent states
.The word storm is synonymous with images of destruction –strong
winds lashing at trees and buildings , intense precipitation flooding
towns or dumping meters of snow , large seas eroding beaches and
coastal properties , and rapid surges in ocean levels inundating entire
islands and vast lowland areas. At the same time , storms are essential to
human life and an integral part of the global weather and natural
ecosystems . storms help break droughts by delevering much needed
water to drought-stricken areas , thereby recharging reservoirs , river
systems and underground aquifers . Many ecosystems are also reliant on
the episodic arrival of large storms for their rejuvenation after extended
periods of calm , stable conditions .
The term storm is defined as « a disturbance of the atmosphere marked
by winds and usually by rain , snow , hail sleet or thunder and lightening
« .
There are several important features about coastal storms that make
them unique from other storm types (thunderstorm ,and snowstorm for
instance) and hence particularly challenging to define and categorize.
These features include :
- The location of the atmospheric disturbance relative to the impact
area.
- The diversity of environments in which coastal storms occur.
- The ways in which these diverse environments respond to the
same environmental forcing.
- The timing and duration of the storm.
Coastal erosion :
Erosion is said to occur along a coast when the quantity of loss of
sediments surpasses the quantity supplied to it. Any beach is supposed
to be in equilibrum , when the sediment movement for a period of a
few years is considered. However , some beaches experience excessive